id: P16278
gene_symbol: GLB1
product_type: PROTEIN
status: INITIALIZED
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: GLB1 encodes lysosomal acid beta-galactosidase (beta-Gal), a glycosyl
  hydrolase family 35 exoglycosidase (EC 3.2.1.23) that catalyzes the hydrolysis of
  terminal non-reducing beta-D-galactose residues from beta-D-galactosides. Acting
  within the acidic lysosomal lumen, it degrades the ganglioside GM1 (and its asialo
  derivative GA1) by removing the terminal galactose, and degrades the glycosaminoglycan
  keratan sulfate as well as galactose-terminated glycoproteins and oligosaccharides.
  The mature enzyme is a homodimer/high-molecular-weight multimer that functions in
  a lysosomal multienzyme complex with protective protein/cathepsin A (CTSA/PPCA),
  neuraminidase-1 (NEU1), and N-acetylgalactosamine-6-sulfate sulfatase (GALNS); CTSA
  is required to stabilize the active multimer. It is synthesized as a precursor that
  is processed through the endoplasmic reticulum and Golgi before reaching the lysosome.
  Loss of enzyme activity causes the autosomal recessive lysosomal storage diseases
  GM1-gangliosidosis (types 1, 2, and 3) and mucopolysaccharidosis type IVB (Morquio
  B syndrome), which are allelic. A catalytically inactive, alternatively spliced isoform
  (isoform 2; the elastin-binding protein, EBP) instead localizes to the perinuclear
  cytoplasm/cell surface and participates in elastic-fiber assembly (elastogenesis).
alternative_products:
- name: '1'
  id: P16278-1
- name: 2 (Beta-galactosidase-related protein)
  id: P16278-2, P16279-1
  sequence_note: VSP_031241
- name: '3'
  id: P16278-3
  sequence_note: VSP_039974
existing_annotations:
- term:
    id: GO:0005764
    label: lysosome
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: Phylogenetic (IBA) annotation placing active beta-galactosidase in the
      lysosome. This is well supported for GLB1 isoform 1 and represents the core
      site of action.
    action: ACCEPT
    reason: GLB1 is a lysosomal acid hydrolase (pH optimum 4.5-5.5) whose mature enzyme
      resides and acts in the lysosome; immunoelectron microscopy shows mature high-molecular-weight
      beta-Gal multimers essentially restricted to the lysosome. is_active_in lysosome
      is the appropriate core cellular-component/site-of-action term.
    supported_by:
    - reference_id: PMID:3084261
      supporting_text: In the lysosomes virtually all beta-gal
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0019388
    label: galactose catabolic process
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: Phylogenetic (IBA) annotation to galactose catabolic process, reflecting
      the release of galactose from galactoside substrates.
    action: KEEP_AS_NON_CORE
    reason: By hydrolyzing terminal beta-galactose, GLB1 liberates free galactose,
      so participation in galactose catabolism is defensible. However, the biologically
      salient GLB1 catabolic processes are the turnover of gangliosides and glycosaminoglycans/glycoproteins;
      release of free galactose is a downstream consequence rather than the core physiological
      role. Retained as non-core.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Cleaves beta-linked terminal galactosyl residues from gangliosides,
        glycoproteins, and glycosaminoglycans.
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: Phylogenetic (IBA) annotation to beta-galactosidase activity, the defining
      molecular function of GLB1.
    action: ACCEPT
    reason: This is the core molecular function. Human beta-Gal hydrolyzes terminal
      non-reducing beta-D-galactose residues (EC 3.2.1.23), directly demonstrated
      biochemically and structurally. The IBA is at the correct level of specificity.
    supported_by:
    - reference_id: PMID:22128166
      supporting_text: exoglycosidase that catalyzes the hydrolysis of terminal
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Hydrolysis of terminal non-reducing beta-D-galactose residues
        in beta-D-galactosides.
- term:
    id: GO:0004553
    label: hydrolase activity, hydrolyzing O-glycosyl compounds
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: InterPro-based (IEA) parent term for O-glycosyl hydrolase activity, the
      general class to which beta-galactosidase activity belongs.
    action: KEEP_AS_NON_CORE
    reason: Correct but less informative than the specific child term GO:0004565 beta-galactosidase
      activity, which is separately annotated. Retained as a valid, more general parent
      but not core.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Hydrolysis of terminal non-reducing beta-D-galactose residues
        in beta-D-galactosides.
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: enables
  review:
    summary: Automated (IEA) annotation to beta-galactosidase activity via ARBA/InterPro
      and EC:3.2.1.23.
    action: ACCEPT
    reason: Correct core molecular function, consistent with experimental and phylogenetic
      annotations to the same term.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Hydrolysis of terminal non-reducing beta-D-galactose residues
        in beta-D-galactosides.
- term:
    id: GO:0005764
    label: lysosome
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: Automated (IEA) subcellular-location annotation to lysosome, consistent
      with UniProt SubCell mapping.
    action: ACCEPT
    reason: GLB1 isoform 1 is a lysosomal enzyme; this matches experimental localization
      evidence.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0005975
    label: carbohydrate metabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: involved_in
  review:
    summary: InterPro-based (IEA) high-level annotation to carbohydrate metabolic
      process.
    action: KEEP_AS_NON_CORE
    reason: True but very general. The specific catabolic roles (ganglioside catabolism,
      keratan sulfate proteoglycan catabolism) capture the biology more informatively.
      Retained as a valid general parent, non-core.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Cleaves beta-linked terminal galactosyl residues from gangliosides,
        glycoproteins, and glycosaminoglycans.
- term:
    id: GO:0048471
    label: perinuclear region of cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: UniProt SubCell-mapped (IEA) location to the perinuclear region of cytoplasm.
    action: KEEP_AS_NON_CORE
    reason: This location corresponds specifically to the catalytically inactive isoform
      2 (elastin-binding protein/EBP), which UniProt notes is localized to the perinuclear
      area of the cytoplasm but not to lysosomes. It is not the location of the catalytic
      lysosomal enzyme and is not a core function of GLB1 the beta-galactosidase; kept
      as non-core because it is a valid isoform-2 location.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Localized to the perinuclear area of the cytoplasm but not to
        lysosomes.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  qualifier: enables
  review:
    summary: IPI protein-binding annotations from a systematic binary (Y2H) interactome
      screen, reporting interactions with the membrane proteins GOLM1, SLC10A6, SLC30A2,
      and SLC7A1.
    action: MARK_AS_OVER_ANNOTATED
    reason: 'GO:0005515 protein binding is uninformative and does not describe a molecular
      function of the enzyme. The reported partners (GOLM1 and several SLC transporters)
      are from a high-throughput binary interactome map and have no established physiological
      relationship to lysosomal beta-galactosidase; these are most likely non-physiological
      screen hits. Per curation policy this bare protein-binding IPI is marked as over-annotated
      rather than removed.'
    supported_by:
    - reference_id: PMID:32296183
      supporting_text: A reference map of the human binary protein interactome.
- term:
    id: GO:0006516
    label: glycoprotein catabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: Ortholog-transfer (IEA) annotation to glycoprotein catabolic process.
    action: ACCEPT
    reason: GLB1 removes terminal beta-galactose from N-linked and O-linked glycans
      of glycoproteins; galactose-terminated glycoprotein-derived glycans accumulate
      when the enzyme is deficient, confirming a role in glycoprotein/glycan catabolism.
    supported_by:
    - reference_id: PMID:31720227
      supporting_text: N-linked glycan structures that have galactose at their
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Cleaves beta-linked terminal galactosyl residues from gangliosides,
        glycoproteins, and glycosaminoglycans.
- term:
    id: GO:0006689
    label: ganglioside catabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: Automated (IEA) annotation to ganglioside catabolic process, a core biological
      role of GLB1.
    action: ACCEPT
    reason: Beta-Gal removes the terminal galactose of GM1 ganglioside (converting
      GM1 to GM2) and of its asialo derivative GA1; deficiency causes lysosomal accumulation
      of GM1 and GA1 (GM1-gangliosidosis). This is a well-established core catabolic
      function.
    supported_by:
    - reference_id: PMID:31720227
      supporting_text: leads to the lysosomal accumulation of GM1 and its asialo derivative
        GA1
- term:
    id: GO:0016936
    label: galactoside binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: Ortholog-transfer (IEA) annotation to galactoside binding.
    action: KEEP_AS_NON_CORE
    reason: Substrate (galactoside) binding is intrinsic to the enzyme's catalytic
      mechanism (the active site binds the beta-D-galactose moiety), so the annotation
      is defensible, but it is subsumed by the catalytic beta-galactosidase activity
      term and is not independently core.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: /ligand="beta-D-galactose"
- term:
    id: GO:0019388
    label: galactose catabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: Ortholog-transfer (IEA) duplicate of the galactose catabolic process
      annotation.
    action: KEEP_AS_NON_CORE
    reason: Same rationale as the IBA annotation to GO:0019388; release of free galactose
      is a downstream consequence of GLB1 activity rather than its core physiological
      role.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Cleaves beta-linked terminal galactosyl residues from gangliosides,
        glycoproteins, and glycosaminoglycans.
- term:
    id: GO:0042340
    label: keratan sulfate proteoglycan catabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: Automated (IEA) annotation to keratan sulfate proteoglycan catabolic
      process, a core biological role of GLB1.
    action: ACCEPT
    reason: GLB1 removes terminal beta-galactose from keratan sulfate; enzyme deficiency
      causes keratan sulfate accumulation and Morquio B disease / GM1-gangliosidosis.
      This is a core catabolic function.
    supported_by:
    - reference_id: PMID:22128166
      supporting_text: accumulations of the β-Gal substrates, G M1 ganglioside, and
        keratan sulfate
- term:
    id: GO:0051413
    label: response to cortisone
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: Electronic annotation to response to cortisone, transferred from a rat
      ortholog.
    action: MARK_AS_OVER_ANNOTATED
    reason: This is an ortholog-transferred (Ensembl Compara) electronic annotation
      with no human experimental support and no clear connection to the enzyme's molecular
      function. A transcriptional/physiological response to a steroid is a peripheral
      phenomenon at best and is likely an over-annotation for the human gene; there
      is no supporting evidence in the cached literature or UniProt.
    supported_by:
    - reference_id: GO_REF:0000107
      supporting_text: Automatic transfer of experimentally verified manual GO annotation
        data to orthologs using Ensembl Compara
- term:
    id: GO:1904016
    label: response to Thyroglobulin triiodothyronine
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: Electronic annotation to response to thyroglobulin triiodothyronine,
      transferred from a rat ortholog.
    action: MARK_AS_OVER_ANNOTATED
    reason: Ortholog-transferred electronic annotation with no human experimental
      support and no relationship to the enzyme's catalytic function. Likely an over-annotation
      for the human gene.
    supported_by:
    - reference_id: GO_REF:0000107
      supporting_text: Automatic transfer of experimentally verified manual GO annotation
        data to orthologs using Ensembl Compara
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-2265534
  qualifier: enables
  review:
    summary: Reactome TAS annotation (from the pathway describing defective GLB1 failing
      to hydrolyze a glycosaminoglycan) supporting beta-galactosidase activity.
    action: ACCEPT
    reason: Correct core molecular function, consistent with all other beta-galactosidase
      activity annotations.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Hydrolysis of terminal non-reducing beta-D-galactose residues
        in beta-D-galactosides.
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9036061
  qualifier: enables
  review:
    summary: Reactome TAS annotation supporting beta-galactosidase activity.
    action: ACCEPT
    reason: Correct core molecular function.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: Hydrolysis of terminal non-reducing beta-D-galactose residues
        in beta-D-galactosides.
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: EXP
  original_reference_id: PMID:15714521
  qualifier: enables
  review:
    summary: Experimental (EXP) annotation to beta-galactosidase activity from expression
      studies of GLB1 mutations in GM1-gangliosidosis patients, in which GLB1 enzyme
      activity was measured.
    action: ACCEPT
    reason: Direct experimental support for the core beta-galactosidase molecular
      function; the study measured GLB1 enzyme activity and showed mutations affect
      it.
    supported_by:
    - reference_id: PMID:15714521
      supporting_text: the identified mutations affect GLB1 enzyme activity and/or
        stability
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: EXP
  original_reference_id: PMID:19472408
  qualifier: enables
  review:
    summary: Experimental (EXP) annotation to beta-galactosidase activity from expression
      analysis of catalytic-site missense mutations, which measured beta-Gal activity
      of wild-type and mutant enzymes.
    action: ACCEPT
    reason: Direct experimental support for the core molecular function; catalytic-site
      mutants showed significantly reduced beta-Gal activity relative to normal enzyme.
    supported_by:
    - reference_id: PMID:19472408
      supporting_text: significantly reduced beta-Gal activities (<10% of normal) upon
        expression in
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: EXP
  original_reference_id: PMID:2511208
  qualifier: enables
  review:
    summary: Experimental (EXP) annotation to beta-galactosidase activity; the classic
      lysosomal isoform (long cDNA) was shown to be catalytically active in COS-1
      cells.
    action: ACCEPT
    reason: Direct experimental support that GLB1 isoform 1 encodes an active beta-galactosidase
      capable of correcting activity in GM1-gangliosidosis fibroblasts.
    supported_by:
    - reference_id: PMID:2511208
      supporting_text: Only the long protein is catalytically active under the
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: EXP
  original_reference_id: PMID:8200356
  qualifier: enables
  review:
    summary: Experimental (EXP) annotation to beta-galactosidase activity; GM1-beta-galactosidase
      (EC 3.2.1.23) was assayed on lactosylceramide and GM1 substrates.
    action: ACCEPT
    reason: Direct biochemical support for beta-galactosidase activity on glycosphingolipid
      substrates (GM1, lactosylceramide), stimulated by saposin activator proteins.
    supported_by:
    - reference_id: PMID:8200356
      supporting_text: 'glycosphingolipids: GM1-beta-galactosidase (EC 3.2.1.23) and'
- term:
    id: GO:0005764
    label: lysosome
  evidence_type: EXP
  original_reference_id: PMID:2511208
  qualifier: located_in
  review:
    summary: Experimental (EXP) annotation localizing GLB1 (classic isoform) to the
      lysosome.
    action: ACCEPT
    reason: The classic lysosomal beta-galactosidase isoform localizes to lysosomes;
      UniProt records the isoform 1 lysosomal location supported by this reference.
      Core site of action.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0005764
    label: lysosome
  evidence_type: EXP
  original_reference_id: PMID:3084261
  qualifier: located_in
  review:
    summary: Experimental (EXP) immunoelectron-microscopy annotation localizing mature
      beta-galactosidase to the lysosome.
    action: ACCEPT
    reason: Immunoelectron microscopy showed that essentially all mature beta-Gal
      exists as a high-molecular-weight multimer within the lysosome. Strong experimental
      support for the core lysosomal location.
    supported_by:
    - reference_id: PMID:3084261
      supporting_text: In the lysosomes virtually all beta-gal
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IDA
  original_reference_id: PMID:11927518
  qualifier: enables
  review:
    summary: IDA annotation to beta-galactosidase activity from a study of endothelial
      cell senescence in atherosclerosis that used senescence-associated beta-galactosidase
      (SA-beta-gal) histochemical staining.
    action: MARK_AS_OVER_ANNOTATED
    reason: This paper measured senescence-associated beta-galactosidase (SA-beta-gal)
      activity as a histochemical marker of cell senescence in atherosclerotic tissue,
      not as a biochemical characterization of the GLB1 enzyme or its substrate specificity.
      While GLB1 is the enzyme responsible for the SA-beta-gal signal, this is a peripheral
      phenotypic readout; the core beta-galactosidase activity function is far better
      supported by the dedicated enzymology and structural papers. Kept but marked
      over-annotated.
    supported_by:
    - reference_id: PMID:11927518
      supporting_text: Senescence-associated beta-galactosidase (beta-gal)
- term:
    id: GO:0005975
    label: carbohydrate metabolic process
  evidence_type: IDA
  original_reference_id: PMID:11927518
  qualifier: involved_in
  review:
    summary: IDA annotation to carbohydrate metabolic process from the same SA-beta-gal
      senescence study.
    action: MARK_AS_OVER_ANNOTATED
    reason: The supporting paper is about endothelial senescence detected via SA-beta-gal
      staining and does not characterize carbohydrate metabolism by GLB1. This is
      both a very general term and derived from a peripheral phenotypic assay; over-annotated.
    supported_by:
    - reference_id: PMID:11927518
      supporting_text: Senescence-associated beta-galactosidase (beta-gal)
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IMP
  original_reference_id: PMID:8112731
  qualifier: enables
  review:
    summary: IMP annotation to beta-galactosidase activity from analysis of mutant
      enzyme processing and residual catalytic activity in beta-galactosidase deficiency.
    action: ACCEPT
    reason: The study assayed catalytic activity of GLB1 mutant enzymes (e.g., low
      catalytic activity in normally processed Morquio B enzyme), supporting beta-galactosidase
      activity as the gene's function via loss/alteration of activity in patients.
    supported_by:
    - reference_id: PMID:8112731
      supporting_text: transported to lysosomes, but its catalytic activity was low
- term:
    id: GO:0005764
    label: lysosome
  evidence_type: IMP
  original_reference_id: PMID:8112731
  qualifier: is_active_in
  review:
    summary: IMP annotation placing active beta-galactosidase in the lysosome, from
      study of mutant enzyme trafficking and maturation.
    action: ACCEPT
    reason: The study tracked processing/transport of GLB1 to lysosomes and residual
      lysosomal activity, supporting the lysosome as the site where the enzyme is
      active. Core location.
    supported_by:
    - reference_id: PMID:8112731
      supporting_text: transported to lysosomes, but its catalytic activity was low
- term:
    id: GO:0006516
    label: glycoprotein catabolic process
  evidence_type: IMP
  original_reference_id: PMID:31720227
  qualifier: involved_in
  review:
    summary: IMP annotation to glycoprotein catabolic process, from characterization
      of glycan substrates accumulating in GM1-gangliosidosis (GLB1 deficiency).
    action: ACCEPT
    reason: GLB1 deficiency causes accumulation of N-linked and O-linked glycans with
      terminal beta-linked galactose, demonstrating that GLB1 is required for catabolism
      of glycoprotein-derived glycans (a "broad oligosaccharidosis"). Core catabolic
      role.
    supported_by:
    - reference_id: PMID:31720227
      supporting_text: N-linked glycans with terminal beta-linked
- term:
    id: GO:0006689
    label: ganglioside catabolic process
  evidence_type: IMP
  original_reference_id: PMID:31720227
  qualifier: involved_in
  review:
    summary: IMP annotation to ganglioside catabolic process, from characterization
      of substrates accumulating in GM1-gangliosidosis.
    action: ACCEPT
    reason: GLB1 deficiency leads to lysosomal accumulation of GM1 and its asialo
      derivative GA1, directly demonstrating GLB1's requirement for ganglioside catabolism.
      Core function.
    supported_by:
    - reference_id: PMID:31720227
      supporting_text: leads to the lysosomal accumulation of GM1 and its asialo derivative
        GA1
- term:
    id: GO:0042340
    label: keratan sulfate proteoglycan catabolic process
  evidence_type: IMP
  original_reference_id: PMID:31720227
  qualifier: involved_in
  review:
    summary: IMP annotation to keratan sulfate proteoglycan catabolic process associated
      with GLB1 deficiency.
    action: ACCEPT
    reason: GLB1 removes terminal beta-galactose from keratan sulfate; its deficiency
      causes accumulation of keratan sulfate and related galactose-terminated glycans
      (underlying Morquio B). Core catabolic function.
    supported_by:
    - reference_id: PMID:31720227
      supporting_text: broad oligosaccharidosis
    - reference_id: PMID:22128166
      supporting_text: accumulations of the β-Gal substrates, G M1 ganglioside, and
        keratan sulfate
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IDA
  original_reference_id: PMID:24737316
  qualifier: enables
  review:
    summary: IDA annotation to beta-galactosidase activity from enzymological characterization
      of purified recombinant human beta-Gal (wild-type and mutants).
    action: ACCEPT
    reason: Direct assay of purified recombinant human beta-Gal established its beta-galactosidase
      enzymology (substrate/inhibitor recognition at the active site). Strong support
      for the core molecular function.
    supported_by:
    - reference_id: PMID:24737316
      supporting_text: enzymological properties of purified recombinant human β-Gal
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22128166
  qualifier: enables
  review:
    summary: IPI protein-binding annotation from the crystal-structure paper, reflecting
      the GLB1 homodimer (self-interaction).
    action: MARK_AS_OVER_ANNOTATED
    reason: GO:0005515 protein binding is uninformative. The underlying observation
      (GLB1 self-association) is more precisely captured by the accompanying protein
      homodimerization activity annotation from the same paper. This bare protein-binding
      term is redundant and non-informative; marked over-annotated per policy rather
      than removed.
    supported_by:
    - reference_id: PMID:22128166
      supporting_text: Human β-Gal is composed of a catalytic TIM barrel domain
- term:
    id: GO:0042803
    label: protein homodimerization activity
  evidence_type: IPI
  original_reference_id: PMID:22128166
  qualifier: enables
  review:
    summary: IPI annotation to protein homodimerization activity, from the crystal
      structure showing that human beta-Gal is a homodimer.
    action: KEEP_AS_NON_CORE
    reason: The crystal structure demonstrates that human beta-Gal forms a homodimer,
      and UniProt records the homodimer subunit structure. This is a real, informative
      molecular-function annotation, but the enzyme's catalytic activity is its core
      function; homodimerization is retained as a valid non-core structural property.
    supported_by:
    - reference_id: PMID:22128166
      supporting_text: crystal structures of human β-Gal
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBUNIT: Homodimer'
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IDA
  original_reference_id: PMID:11927518
  qualifier: located_in
  review:
    summary: IDA annotation localizing beta-galactosidase signal to the cytoplasm,
      from the SA-beta-gal senescence/atherosclerosis study.
    action: MARK_AS_OVER_ANNOTATED
    reason: The bulk (mature) beta-galactosidase is a lysosomal enzyme; the catalytically
      inactive isoform 2 is perinuclear-cytoplasmic. A generic cytoplasm localization
      derived from histochemical SA-beta-gal staining does not reflect the site of
      action of the catalytic enzyme and conflicts with the strong lysosomal localization
      evidence. Kept but marked over-annotated.
    supported_by:
    - reference_id: PMID:11927518
      supporting_text: Senescence-associated beta-galactosidase (beta-gal)
- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-6798751
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to extracellular region via the neutrophil azurophil-granule
      exocytosis pathway.
    action: KEEP_AS_NON_CORE
    reason: GLB1 can be secreted/released during neutrophil degranulation and is detected
      extracellularly, but its physiological site of action is the lysosome. Retained
      as a valid non-core secretory/exocytosis-context location.
    supported_by:
    - reference_id: Reactome:R-HSA-6798751
      supporting_text: Exocytosis of azurophil granule lumen proteins
- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-6800434
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to extracellular region via the ficolin-rich-granule
      exocytosis pathway.
    action: KEEP_AS_NON_CORE
    reason: Same rationale as the other extracellular-region annotation; a secretory
      granule-exocytosis context, not the enzyme's core lysosomal site of action.
    supported_by:
    - reference_id: Reactome:R-HSA-6800434
      supporting_text: Exocytosis of ficolin-rich granule lumen proteins
- term:
    id: GO:0035578
    label: azurophil granule lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-6798751
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to azurophil granule lumen (neutrophil degranulation
      pathway).
    action: KEEP_AS_NON_CORE
    reason: Reflects GLB1's presence in the lumen of neutrophil azurophil granules
      (a lysosome-related organelle) as part of the neutrophil-degranulation program.
      A plausible non-core location; not the primary site of the enzyme's catabolic
      function.
    supported_by:
    - reference_id: Reactome:R-HSA-6798751
      supporting_text: Exocytosis of azurophil granule lumen proteins
- term:
    id: GO:1904813
    label: ficolin-1-rich granule lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-6800434
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to ficolin-1-rich granule lumen (neutrophil degranulation
      pathway).
    action: KEEP_AS_NON_CORE
    reason: Reflects GLB1's presence in the lumen of neutrophil ficolin-1-rich granules
      as part of the neutrophil-degranulation program. Plausible non-core location.
    supported_by:
    - reference_id: Reactome:R-HSA-6800434
      supporting_text: Exocytosis of ficolin-rich granule lumen proteins
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: IMP
  original_reference_id: PMID:25936995
  qualifier: enables
  review:
    summary: IMP annotation to beta-galactosidase activity from a large GLB1 mutation
      study in GM1-gangliosidosis patients, where deficiency of the beta-D-galactosidase
      enzyme underlies disease.
    action: ACCEPT
    reason: The study links GLB1 mutations to deficiency of the beta-D-galactosidase
      enzyme, and predicts novel mutations affect protein function/structure, supporting
      the core catalytic function via loss-of-function evidence.
    supported_by:
    - reference_id: PMID:25936995
      supporting_text: leading to the deficiency of the enzyme
- term:
    id: GO:0070062
    label: extracellular exosome
  evidence_type: HDA
  original_reference_id: PMID:23533145
  qualifier: located_in
  review:
    summary: High-throughput proteomics (HDA) detection of GLB1 in exosomes from prostatic
      secretions in urine.
    action: KEEP_AS_NON_CORE
    reason: GLB1 is detected in extracellular exosomes by mass spectrometry, consistent
      with its presence in secretory/extracellular fluids, but this is not its physiological
      site of action. Valid non-core location from a large-scale proteomics survey.
    supported_by:
    - reference_id: PMID:23533145
      supporting_text: exosome preparations were characterized by a shotgun proteomics
        procedure
- term:
    id: GO:0070062
    label: extracellular exosome
  evidence_type: HDA
  original_reference_id: PMID:19056867
  qualifier: located_in
  review:
    summary: High-throughput proteomics (HDA) detection of GLB1 in urinary exosomes.
    action: KEEP_AS_NON_CORE
    reason: GLB1 was identified in the urinary-exosome proteome by LC-MS/MS. A valid
      non-core extracellular-vesicle location, not the enzyme's site of action.
    supported_by:
    - reference_id: PMID:19056867
      supporting_text: profile the proteome of human urinary exosomes
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-2265534
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (defective GLB1 glycosaminoglycan
      hydrolysis pathway).
    action: ACCEPT
    reason: The lysosomal lumen is the precise compartment where the soluble beta-galactosidase
      acts. This is an accurate, informative core location.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9036061
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen.
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1605624
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (mobilized GM1 hydrolysis pathway).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen on mobilized
      GM1.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1605724
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen.
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1606312
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyzes SapB/C:LacCer
      pathway).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen on lactosylceramide
      presented by saposins.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1630306
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyses a glycosaminoglycan
      pathway).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts on glycosaminoglycans in the lysosomal
      lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-2090079
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyses keratan sulfate
      linker chain pathway).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-4084999
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (from a sialic-acid-metabolism
      pathway that co-locates the CTSA/NEU1/GLB1 complex components).
    action: ACCEPT
    reason: Accurate core location; GLB1 resides in the lysosomal lumen alongside
      the multienzyme complex.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-4341669
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (defective NEU1 pathway that
      includes GLB1 complex context).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9638120
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen.
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0043202
    label: lysosomal lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9840795
  qualifier: located_in
  review:
    summary: Reactome TAS annotation to lysosomal lumen (beta-galactosidases hydrolyze
      GM2A:GA1 to GM2A:GA2 pathway).
    action: ACCEPT
    reason: Accurate core location; the enzyme acts in the lysosomal lumen on GA1.
    supported_by:
    - reference_id: file:human/GLB1/GLB1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: [Isoform 1]: Lysosome'
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:15498789
  qualifier: enables
  review:
    summary: IPI protein-binding annotation citing the NGX6 nasopharyngeal-carcinoma
      cell-adhesion paper, with interactant PDGFA (UniProtKB:P15311) recorded in GOA.
    action: MARK_AS_OVER_ANNOTATED
    reason: GO:0005515 protein binding is uninformative and does not describe a molecular
      function of the enzyme. The cited paper concerns NGX6 and cell adhesion in nasopharyngeal
      carcinoma and does not establish a physiologically meaningful GLB1 interaction.
      Per policy this bare protein-binding IPI is marked over-annotated rather than
      removed.
    supported_by:
    - reference_id: PMID:15498789
      supporting_text: NGX6 in cell adhesion modulation in nasopharyngeal carcinoma
        cells
- term:
    id: GO:0004565
    label: beta-galactosidase activity
  evidence_type: TAS
  original_reference_id: PMID:3143362
  qualifier: enables
  review:
    summary: TAS annotation to beta-galactosidase activity from the original human
      beta-galactosidase cDNA cloning/expression paper.
    action: ACCEPT
    reason: Expression of the cloned human cDNA increased beta-galactosidase activity,
      establishing that GLB1 encodes an active beta-galactosidase. Core molecular
      function.
    supported_by:
    - reference_id: PMID:3143362
      supporting_text: led to an increase in beta-galactosidase activity
core_functions:
- description: Lysosomal acid beta-galactosidase that hydrolyzes terminal non-reducing
    beta-D-galactose residues from beta-D-galactosides, acting in the lysosomal lumen
    as part of a multienzyme complex with CTSA/PPCA and NEU1.
  molecular_function:
    id: GO:0004565
    label: beta-galactosidase activity
  directly_involved_in:
  - id: GO:0006689
    label: ganglioside catabolic process
  locations:
  - id: GO:0043202
    label: lysosomal lumen
  supported_by:
  - reference_id: PMID:31720227
    supporting_text: leads to the lysosomal accumulation of GM1 and its asialo derivative
      GA1
  - reference_id: PMID:22128166
    supporting_text: exoglycosidase that catalyzes the hydrolysis of terminal
- description: Lysosomal acid beta-galactosidase that degrades the glycosaminoglycan
    keratan sulfate (and galactose-terminated glycoprotein/oligosaccharide glycans)
    by removing terminal beta-galactose residues in the lysosome.
  molecular_function:
    id: GO:0004565
    label: beta-galactosidase activity
  directly_involved_in:
  - id: GO:0042340
    label: keratan sulfate proteoglycan catabolic process
  locations:
  - id: GO:0005764
    label: lysosome
  supported_by:
  - reference_id: PMID:22128166
    supporting_text: accumulations of the β-Gal substrates, G M1 ganglioside, and
      keratan sulfate
  - reference_id: file:human/GLB1/GLB1-uniprot.txt
    supporting_text: Cleaves beta-linked terminal galactosyl residues from gangliosides,
      glycoproteins, and glycosaminoglycans.
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO
    terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: file:human/GLB1/GLB1-uniprot.txt
  title: UniProtKB entry P16278 (BGAL_HUMAN), Beta-galactosidase
  findings: []
- id: PMID:11927518
  title: 'Endothelial cell senescence in human atherosclerosis: role of telomere in
    endothelial dysfunction.'
  findings: []
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: Measures senescence-associated beta-galactosidase (SA-beta-gal)
      histochemical staining as a senescence marker; does not biochemically characterize
      GLB1 substrate specificity or localization. The IDA beta-galactosidase-activity,
      carbohydrate-metabolic-process, and cytoplasm annotations derived from it are
      over-annotations.
- id: PMID:15498789
  title: Role of a novel EGF-like domain-containing gene NGX6 in cell adhesion modulation
    in nasopharyngeal carcinoma cells.
  findings: []
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: Paper concerns NGX6 and cell adhesion in nasopharyngeal carcinoma;
      does not establish a physiologically meaningful GLB1 protein interaction. Supports
      only a bare, uninformative protein-binding annotation.
- id: PMID:15714521
  title: Role of beta-galactosidase and elastin binding protein in lysosomal and nonlysosomal
    complexes of patients with GM1-gangliosidosis.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Establishes the lysosomal multienzyme complex of GLB1 with PPCA/CTSA,
      NEU1, and GALNS, and shows disease mutations affect GLB1 activity/stability.
- id: PMID:19056867
  title: Large-scale proteomics and phosphoproteomics of urinary exosomes.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Large-scale proteomics detecting GLB1 in urinary exosomes; supports
      a non-core extracellular-exosome location only.
- id: PMID:19472408
  title: 'GM1 gangliosidosis and Morquio B disease: expression analysis of missense
    mutations affecting the catalytic site of acid beta-galactosidase.'
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Expression analysis of catalytic-site missense mutants directly
      measured beta-Gal activity; supports the core molecular function.
- id: PMID:22128166
  title: 'Crystal structure of human β-galactosidase: structural basis of Gm1 gangliosidosis
    and morquio B diseases.'
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Crystal structure defining beta-Gal as an exoglycosidase hydrolyzing
      terminal beta-linked galactose, the homodimer, TIM-barrel active site, and the
      GM1/keratan sulfate substrates.
- id: PMID:23533145
  title: In-depth proteomic analyses of exosomes isolated from expressed prostatic
    secretions in urine.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Shotgun proteomics detecting GLB1 in prostatic-secretion exosomes;
      supports a non-core extracellular-exosome location only.
- id: PMID:24737316
  title: Structural basis of pharmacological chaperoning for human β-galactosidase.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Enzymological characterization of purified recombinant human beta-Gal
      (WT and mutants) and active-site ligand recognition; supports the core catalytic
      function.
- id: PMID:2511208
  title: Alternative splicing of beta-galactosidase mRNA generates the classic lysosomal
    enzyme and a beta-galactosidase-related protein.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Shows the classic long isoform is the catalytically active lysosomal
      enzyme, distinct from the inactive beta-galactosidase-related protein (isoform
      2 / EBP).
- id: PMID:25936995
  title: Recurrent and novel GLB1 mutations in India.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Large GLB1 mutation series in GM1-gangliosidosis; links mutations
      to beta-D-galactosidase deficiency and predicts functional/structural impact.
- id: PMID:3084261
  title: Immunoelectron microscopical localization of lysosomal beta-galactosidase
    and its precursor forms in normal and mutant human fibroblasts.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Immunoelectron microscopy localizing mature high-MW beta-Gal multimers
      to the lysosome, with precursor forms in RER/Golgi; PPCA restores multimers.
- id: PMID:3143362
  title: Cloning, sequencing, and expression of cDNA for human beta-galactosidase.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Original cloning/expression of human beta-galactosidase cDNA; expression
      increased beta-galactosidase activity.
- id: PMID:31720227
  title: Characterization of glycan substrates accumulating in GM1 Gangliosidosis.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Defines GLB1 as a lysosomal hydrolase removing beta-galactose from
      the non-reducing end of glycans; deficiency causes accumulation of GM1, GA1,
      and N-/O-linked galactose-terminated glycans (broad oligosaccharidosis).
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings: []
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: High-throughput binary (Y2H) interactome map; the reported GLB1
      partners (GOLM1, SLC10A6, SLC30A2, SLC7A1) are likely non-physiological screen
      hits and support only a bare protein-binding annotation.
- id: PMID:8112731
  title: Intracellular processing and maturation of mutant gene products in hereditary
    beta-galactosidase deficiency (beta-galactosidosis).
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Analyzes processing/trafficking and residual catalytic activity
      of GLB1 mutant enzymes across GM1-gangliosidosis and Morquio B forms.
- id: PMID:8200356
  title: Hydrolysis of lactosylceramide by human galactosylceramidase and GM1-beta-galactosidase
    in a detergent-free system and its stimulation by sphingolipid activator proteins,
    sap-B and sap-C. Activator proteins stimulate lactosylceramide hydrolysis.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Biochemical assay of GM1-beta-galactosidase (EC 3.2.1.23) on GM1
      and lactosylceramide, stimulated by saposin activator proteins.
- id: Reactome:R-HSA-1605624
  title: Beta-galactosidases hydrolyse mobilized GM1 to mobilized GM2
  findings: []
- id: Reactome:R-HSA-1605724
  title: NEU1,4 hydrolyze PSAP(195-273):GM3:PE
  findings: []
- id: Reactome:R-HSA-1606312
  title: GLB1 hydrolyzes SapB/C:LacCer
  findings: []
- id: Reactome:R-HSA-1630306
  title: GLB1 hydrolyses a glycosaminoglycan
  findings: []
- id: Reactome:R-HSA-2090079
  title: GLB1 hydrolyses linker chain(2)
  findings: []
- id: Reactome:R-HSA-2265534
  title: Defective GLB1 does not hydrolyse a glycosaminoglycan
  findings: []
- id: Reactome:R-HSA-4084999
  title: NEU1 hydrolyses Neu5Ac from glycoconjugates
  findings: []
- id: Reactome:R-HSA-4341669
  title: Defective NEU1 does not hydrolyse Neu5Ac from glycoconjugates
  findings: []
- id: Reactome:R-HSA-6798751
  title: Exocytosis of azurophil granule lumen proteins
  findings: []
- id: Reactome:R-HSA-6800434
  title: Exocytosis of ficolin-rich granule lumen proteins
  findings: []
- id: Reactome:R-HSA-9036061
  title: Defective GLB1 does not hydrolyse linker chain(2)
  findings: []
- id: Reactome:R-HSA-9638120
  title: NEU4 hydrolyses Neu5Ac from glycoconjugates
  findings: []
- id: Reactome:R-HSA-9840795
  title: Beta-galactosidases hydrolyze GM2A:GA1 to GM2A:GA2
  findings: []