GLB1

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0005764 lysosome	IBA GO_REF:0000033	ACCEPT	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. 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. Supporting Evidence: PMID:3084261 In the lysosomes virtually all beta-gal file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0019388 galactose catabolic process	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Phylogenetic (IBA) annotation to galactose catabolic process, reflecting the release of galactose from galactoside substrates. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans.
GO:0004565 beta-galactosidase activity	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) annotation to beta-galactosidase activity, the defining molecular function of GLB1. 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. Supporting Evidence: PMID:22128166 exoglycosidase that catalyzes the hydrolysis of terminal file:human/GLB1/GLB1-uniprot.txt Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
GO:0004553 hydrolase activity, hydrolyzing O-glycosyl compounds	IEA GO_REF:0000002	KEEP AS NON CORE	Summary: InterPro-based (IEA) parent term for O-glycosyl hydrolase activity, the general class to which beta-galactosidase activity belongs. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
GO:0004565 beta-galactosidase activity	IEA GO_REF:0000120	ACCEPT	Summary: Automated (IEA) annotation to beta-galactosidase activity via ARBA/InterPro and EC:3.2.1.23. Reason: Correct core molecular function, consistent with experimental and phylogenetic annotations to the same term. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
GO:0005764 lysosome	IEA GO_REF:0000120	ACCEPT	Summary: Automated (IEA) subcellular-location annotation to lysosome, consistent with UniProt SubCell mapping. Reason: GLB1 isoform 1 is a lysosomal enzyme; this matches experimental localization evidence. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0005975 carbohydrate metabolic process	IEA GO_REF:0000002	KEEP AS NON CORE	Summary: InterPro-based (IEA) high-level annotation to carbohydrate metabolic process. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans.
GO:0048471 perinuclear region of cytoplasm	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: UniProt SubCell-mapped (IEA) location to the perinuclear region of cytoplasm. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Localized to the perinuclear area of the cytoplasm but not to lysosomes.
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	MARK AS OVER ANNOTATED	Summary: IPI protein-binding annotations from a systematic binary (Y2H) interactome screen, reporting interactions with the membrane proteins GOLM1, SLC10A6, SLC30A2, and SLC7A1. 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. Supporting Evidence: PMID:32296183 A reference map of the human binary protein interactome.
GO:0006516 glycoprotein catabolic process	IEA GO_REF:0000107	ACCEPT	Summary: Ortholog-transfer (IEA) annotation to glycoprotein catabolic process. 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. Supporting Evidence: PMID:31720227 N-linked glycan structures that have galactose at their file:human/GLB1/GLB1-uniprot.txt Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans.
GO:0006689 ganglioside catabolic process	IEA GO_REF:0000120	ACCEPT	Summary: Automated (IEA) annotation to ganglioside catabolic process, a core biological role of GLB1. 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. Supporting Evidence: PMID:31720227 leads to the lysosomal accumulation of GM1 and its asialo derivative GA1
GO:0016936 galactoside binding	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: Ortholog-transfer (IEA) annotation to galactoside binding. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt /ligand="beta-D-galactose"
GO:0019388 galactose catabolic process	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: Ortholog-transfer (IEA) duplicate of the galactose catabolic process annotation. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans.
GO:0042340 keratan sulfate proteoglycan catabolic process	IEA GO_REF:0000120	ACCEPT	Summary: Automated (IEA) annotation to keratan sulfate proteoglycan catabolic process, a core biological role of GLB1. 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. Supporting Evidence: PMID:22128166 accumulations of the β-Gal substrates, G M1 ganglioside, and keratan sulfate
GO:0051413 response to cortisone	IEA GO_REF:0000107	MARK AS OVER ANNOTATED	Summary: Electronic annotation to response to cortisone, transferred from a rat ortholog. 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. Supporting Evidence: GO_REF:0000107 Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
GO:1904016 response to Thyroglobulin triiodothyronine	IEA GO_REF:0000107	MARK AS OVER ANNOTATED	Summary: Electronic annotation to response to thyroglobulin triiodothyronine, transferred from a rat ortholog. 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. Supporting Evidence: GO_REF:0000107 Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
GO:0004565 beta-galactosidase activity	TAS Reactome:R-HSA-2265534	ACCEPT	Summary: Reactome TAS annotation (from the pathway describing defective GLB1 failing to hydrolyze a glycosaminoglycan) supporting beta-galactosidase activity. Reason: Correct core molecular function, consistent with all other beta-galactosidase activity annotations. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
GO:0004565 beta-galactosidase activity	TAS Reactome:R-HSA-9036061	ACCEPT	Summary: Reactome TAS annotation supporting beta-galactosidase activity. Reason: Correct core molecular function. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt Hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides.
GO:0004565 beta-galactosidase activity	EXP PMID:15714521 Role of beta-galactosidase and elastin binding protein in ly...	ACCEPT	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. Reason: Direct experimental support for the core beta-galactosidase molecular function; the study measured GLB1 enzyme activity and showed mutations affect it. Supporting Evidence: PMID:15714521 the identified mutations affect GLB1 enzyme activity and/or stability
GO:0004565 beta-galactosidase activity	EXP PMID:19472408 GM1 gangliosidosis and Morquio B disease: expression analysi...	ACCEPT	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. Reason: Direct experimental support for the core molecular function; catalytic-site mutants showed significantly reduced beta-Gal activity relative to normal enzyme. Supporting Evidence: PMID:19472408 significantly reduced beta-Gal activities (<10% of normal) upon expression in
GO:0004565 beta-galactosidase activity	EXP PMID:2511208 Alternative splicing of beta-galactosidase mRNA generates th...	ACCEPT	Summary: Experimental (EXP) annotation to beta-galactosidase activity; the classic lysosomal isoform (long cDNA) was shown to be catalytically active in COS-1 cells. Reason: Direct experimental support that GLB1 isoform 1 encodes an active beta-galactosidase capable of correcting activity in GM1-gangliosidosis fibroblasts. Supporting Evidence: PMID:2511208 Only the long protein is catalytically active under the
GO:0004565 beta-galactosidase activity	EXP PMID:8200356 Hydrolysis of lactosylceramide by human galactosylceramidase...	ACCEPT	Summary: Experimental (EXP) annotation to beta-galactosidase activity; GM1-beta-galactosidase (EC 3.2.1.23) was assayed on lactosylceramide and GM1 substrates. Reason: Direct biochemical support for beta-galactosidase activity on glycosphingolipid substrates (GM1, lactosylceramide), stimulated by saposin activator proteins. Supporting Evidence: PMID:8200356 glycosphingolipids: GM1-beta-galactosidase (EC 3.2.1.23) and
GO:0005764 lysosome	EXP PMID:2511208 Alternative splicing of beta-galactosidase mRNA generates th...	ACCEPT	Summary: Experimental (EXP) annotation localizing GLB1 (classic isoform) to the lysosome. 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. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0005764 lysosome	EXP PMID:3084261 Immunoelectron microscopical localization of lysosomal beta-...	ACCEPT	Summary: Experimental (EXP) immunoelectron-microscopy annotation localizing mature beta-galactosidase to the lysosome. 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. Supporting Evidence: PMID:3084261 In the lysosomes virtually all beta-gal
GO:0004565 beta-galactosidase activity	IDA PMID:11927518 Endothelial cell senescence in human atherosclerosis: role o...	MARK AS OVER ANNOTATED	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. 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. Supporting Evidence: PMID:11927518 Senescence-associated beta-galactosidase (beta-gal)
GO:0005975 carbohydrate metabolic process	IDA PMID:11927518 Endothelial cell senescence in human atherosclerosis: role o...	MARK AS OVER ANNOTATED	Summary: IDA annotation to carbohydrate metabolic process from the same SA-beta-gal senescence study. 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. Supporting Evidence: PMID:11927518 Senescence-associated beta-galactosidase (beta-gal)
GO:0004565 beta-galactosidase activity	IMP PMID:8112731 Intracellular processing and maturation of mutant gene produ...	ACCEPT	Summary: IMP annotation to beta-galactosidase activity from analysis of mutant enzyme processing and residual catalytic activity in beta-galactosidase deficiency. 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. Supporting Evidence: PMID:8112731 transported to lysosomes, but its catalytic activity was low
GO:0005764 lysosome	IMP PMID:8112731 Intracellular processing and maturation of mutant gene produ...	ACCEPT	Summary: IMP annotation placing active beta-galactosidase in the lysosome, from study of mutant enzyme trafficking and maturation. 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. Supporting Evidence: PMID:8112731 transported to lysosomes, but its catalytic activity was low
GO:0006516 glycoprotein catabolic process	IMP PMID:31720227 Characterization of glycan substrates accumulating in GM1 Ga...	ACCEPT	Summary: IMP annotation to glycoprotein catabolic process, from characterization of glycan substrates accumulating in GM1-gangliosidosis (GLB1 deficiency). 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. Supporting Evidence: PMID:31720227 N-linked glycans with terminal beta-linked
GO:0006689 ganglioside catabolic process	IMP PMID:31720227 Characterization of glycan substrates accumulating in GM1 Ga...	ACCEPT	Summary: IMP annotation to ganglioside catabolic process, from characterization of substrates accumulating in GM1-gangliosidosis. Reason: GLB1 deficiency leads to lysosomal accumulation of GM1 and its asialo derivative GA1, directly demonstrating GLB1's requirement for ganglioside catabolism. Core function. Supporting Evidence: PMID:31720227 leads to the lysosomal accumulation of GM1 and its asialo derivative GA1
GO:0042340 keratan sulfate proteoglycan catabolic process	IMP PMID:31720227 Characterization of glycan substrates accumulating in GM1 Ga...	ACCEPT	Summary: IMP annotation to keratan sulfate proteoglycan catabolic process associated with GLB1 deficiency. 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. Supporting Evidence: PMID:31720227 broad oligosaccharidosis PMID:22128166 accumulations of the β-Gal substrates, G M1 ganglioside, and keratan sulfate
GO:0004565 beta-galactosidase activity	IDA PMID:24737316 Structural basis of pharmacological chaperoning for human β-...	ACCEPT	Summary: IDA annotation to beta-galactosidase activity from enzymological characterization of purified recombinant human beta-Gal (wild-type and mutants). 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. Supporting Evidence: PMID:24737316 enzymological properties of purified recombinant human β-Gal
GO:0005515 protein binding	IPI PMID:22128166 Crystal structure of human β-galactosidase: structural basis...	MARK AS OVER ANNOTATED	Summary: IPI protein-binding annotation from the crystal-structure paper, reflecting the GLB1 homodimer (self-interaction). 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. Supporting Evidence: PMID:22128166 Human β-Gal is composed of a catalytic TIM barrel domain
GO:0042803 protein homodimerization activity	IPI PMID:22128166 Crystal structure of human β-galactosidase: structural basis...	KEEP AS NON CORE	Summary: IPI annotation to protein homodimerization activity, from the crystal structure showing that human beta-Gal is a homodimer. 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. Supporting Evidence: PMID:22128166 crystal structures of human β-Gal file:human/GLB1/GLB1-uniprot.txt SUBUNIT: Homodimer
GO:0005737 cytoplasm	IDA PMID:11927518 Endothelial cell senescence in human atherosclerosis: role o...	MARK AS OVER ANNOTATED	Summary: IDA annotation localizing beta-galactosidase signal to the cytoplasm, from the SA-beta-gal senescence/atherosclerosis study. 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. Supporting Evidence: PMID:11927518 Senescence-associated beta-galactosidase (beta-gal)
GO:0005576 extracellular region	TAS Reactome:R-HSA-6798751	KEEP AS NON CORE	Summary: Reactome TAS annotation to extracellular region via the neutrophil azurophil-granule exocytosis pathway. 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. Supporting Evidence: Reactome:R-HSA-6798751 Exocytosis of azurophil granule lumen proteins
GO:0005576 extracellular region	TAS Reactome:R-HSA-6800434	KEEP AS NON CORE	Summary: Reactome TAS annotation to extracellular region via the ficolin-rich-granule exocytosis pathway. Reason: Same rationale as the other extracellular-region annotation; a secretory granule-exocytosis context, not the enzyme's core lysosomal site of action. Supporting Evidence: Reactome:R-HSA-6800434 Exocytosis of ficolin-rich granule lumen proteins
GO:0035578 azurophil granule lumen	TAS Reactome:R-HSA-6798751	KEEP AS NON CORE	Summary: Reactome TAS annotation to azurophil granule lumen (neutrophil degranulation pathway). 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. Supporting Evidence: Reactome:R-HSA-6798751 Exocytosis of azurophil granule lumen proteins
GO:1904813 ficolin-1-rich granule lumen	TAS Reactome:R-HSA-6800434	KEEP AS NON CORE	Summary: Reactome TAS annotation to ficolin-1-rich granule lumen (neutrophil degranulation pathway). 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. Supporting Evidence: Reactome:R-HSA-6800434 Exocytosis of ficolin-rich granule lumen proteins
GO:0004565 beta-galactosidase activity	IMP PMID:25936995 Recurrent and novel GLB1 mutations in India.	ACCEPT	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. 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. Supporting Evidence: PMID:25936995 leading to the deficiency of the enzyme
GO:0070062 extracellular exosome	HDA PMID:23533145 In-depth proteomic analyses of exosomes isolated from expres...	KEEP AS NON CORE	Summary: High-throughput proteomics (HDA) detection of GLB1 in exosomes from prostatic secretions in urine. 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. Supporting Evidence: PMID:23533145 exosome preparations were characterized by a shotgun proteomics procedure
GO:0070062 extracellular exosome	HDA PMID:19056867 Large-scale proteomics and phosphoproteomics of urinary exos...	KEEP AS NON CORE	Summary: High-throughput proteomics (HDA) detection of GLB1 in urinary exosomes. 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. Supporting Evidence: PMID:19056867 profile the proteome of human urinary exosomes
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2265534	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (defective GLB1 glycosaminoglycan hydrolysis pathway). Reason: The lysosomal lumen is the precise compartment where the soluble beta-galactosidase acts. This is an accurate, informative core location. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-9036061	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen. Reason: Accurate core location; the enzyme acts in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1605624	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (mobilized GM1 hydrolysis pathway). Reason: Accurate core location; the enzyme acts in the lysosomal lumen on mobilized GM1. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1605724	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen. Reason: Accurate core location; the enzyme acts in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1606312	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyzes SapB/C:LacCer pathway). Reason: Accurate core location; the enzyme acts in the lysosomal lumen on lactosylceramide presented by saposins. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1630306	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyses a glycosaminoglycan pathway). Reason: Accurate core location; the enzyme acts on glycosaminoglycans in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2090079	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (GLB1 hydrolyses keratan sulfate linker chain pathway). Reason: Accurate core location; the enzyme acts in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-4084999	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (from a sialic-acid-metabolism pathway that co-locates the CTSA/NEU1/GLB1 complex components). Reason: Accurate core location; GLB1 resides in the lysosomal lumen alongside the multienzyme complex. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-4341669	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (defective NEU1 pathway that includes GLB1 complex context). Reason: Accurate core location; the enzyme acts in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-9638120	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen. Reason: Accurate core location; the enzyme acts in the lysosomal lumen. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-9840795	ACCEPT	Summary: Reactome TAS annotation to lysosomal lumen (beta-galactosidases hydrolyze GM2A:GA1 to GM2A:GA2 pathway). Reason: Accurate core location; the enzyme acts in the lysosomal lumen on GA1. Supporting Evidence: file:human/GLB1/GLB1-uniprot.txt SUBCELLULAR LOCATION: [Isoform 1]: Lysosome
GO:0005515 protein binding	IPI PMID:15498789 Role of a novel EGF-like domain-containing gene NGX6 in cell...	MARK AS OVER ANNOTATED	Summary: IPI protein-binding annotation citing the NGX6 nasopharyngeal-carcinoma cell-adhesion paper, with interactant PDGFA (UniProtKB:P15311) recorded in GOA. 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. Supporting Evidence: PMID:15498789 NGX6 in cell adhesion modulation in nasopharyngeal carcinoma cells
GO:0004565 beta-galactosidase activity	TAS PMID:3143362 Cloning, sequencing, and expression of cDNA for human beta-g...	ACCEPT	Summary: TAS annotation to beta-galactosidase activity from the original human beta-galactosidase cDNA cloning/expression paper. Reason: Expression of the cloned human cDNA increased beta-galactosidase activity, establishing that GLB1 encodes an active beta-galactosidase. Core molecular function. Supporting Evidence: PMID:3143362 led to an increase in beta-galactosidase activity

Gene Description

Existing Annotations Review

Core Functions

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.

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.

References

📚 Additional Documentation

Notes

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