Current review · source evidence · dated notes
Human GALC removes a galactosyl headgroup from galactolipids. The human cloning/expression study reports increased activity in COS-1 cells; cat RNA was a probe intermediate, not the expressed enzyme (PMID:8281145(https://pubmed.ncbi.nlm.nih.gov/8281145/)). Independent purification from human urine, with brain and placenta preparations, supports enzyme identity and activity (PMID:8399327(https://pubmed.ncbi.nlm.nih.gov/8399327/)). Those authentic abstracts were read, but full original assay Methods were not recovered. The current UniProt BIOPHYSICOCHEMICAL PROPERTIES section independently curates a Km of 10 micromolar for the N-acyl substrate and an acid pH optimum of 4.0–4.4 with this PMID; these are used as curated evidence without claiming full-paper assay verification.
The current official products are P54803-1 (685 residues), -3 (662), -4 (659) and -5 (589). Direct FASTAs agree with the declared feature reconstructions. This verifies sequences, not equivalent catalytic activity, processing or localization of every product. The early human cDNA papers describe 669 residues; a later promoter paper reports an upstream in-frame ATG 48 bases before the old start. Neither observation silently establishes every historical construct's identity with a current suffix (PMID:8297359(https://pubmed.ncbi.nlm.nih.gov/8297359/), PMID:9434153(https://pubmed.ncbi.nlm.nih.gov/9434153/)). Proteolytic fragments and electrophoretic bands are not natural splice products.
The normal UniProt record separately curates GalCer hydrolysis (RHEA:14297) and galactosylsphingosine/psychosine hydrolysis (RHEA:43908), the latter with PMID:8399327. Both original broad catabolism annotations remain ACCEPT because a GalCer-only replacement would lose this supported substrate breadth. The production GO-CAM, activity 69729a3800003499, explicitly places GALC in sphingolipid catabolism with PMID:8281145; its exact committed source fields are retained in the evidence archive. Both broad-process rows explicitly cite the same curated catalytic record, whose complete psychosine reaction is quoted once in the UniProt reference finding. The single molecular core describes the GalCer reaction. A specific ontology question records the distinct psychosine reaction without inventing a GO identifier or adding a redundant parent core.
Selected original Methods, Results and captions of the GALC-SapA paper were read. Its principal structure is a mouse 2:2 complex at 3.6 angstrom; a separate limited human pull-down is distinguished. The structure provides a route between the catalytic region and SapA's lipid cavity, but does not contain a resolved lipid-substrate complex. No universal SapC-negative conclusion is imported (PMID:29323104(https://pmc.ncbi.nlm.nih.gov/articles/PMC5764952/)).
The endolysosome paper measures cathepsin substrates and acid-phosphatase activity, not GALC-specific microscopy. Its selected original Methods and Results support the IC setting of an acid hydrolase, with the inference explicit (PMID:27498570(https://pubmed.ncbi.nlm.nih.gov/27498570/)). The single core uses endolysosome lumen; the broader lysosomal-lumen setting is not repeated as a second ancestor location. Lysosomal lumen is part_of lysosome, while endolysosome lumen is_a lysosomal lumen. The official QuickGO path response, retrieved on 2026-11-04, contains that direct is_a edge; its response and hash are preserved in the evidence record. The three lysosome annotations remain ACCEPT under the root-organelle policy. The existing lumen annotations and precise core location supply the subcompartment evidence without replacing the informative organelle claims.
The cancer article is explicitly a review. It states the correct galactosylcerebroside-to-ceramide conversion but is not represented as a newly read primary IDA assay, despite the literal original evidence code (PMID:15657896(https://pubmed.ncbi.nlm.nih.gov/15657896/)). Its downstream cancer hypotheses do not create new apoptosis, migration or adhesion annotations.
There are 20 current source contexts. The genuine native seed has 19 objects because it collapses two otherwise identical activity records. Raw3 is the unextended UniProt context. Raw4 is the separately assigned UOS_MCB context with one conjunction: beta-galactosylceramide input, D-galactose output and N-acylsphingosine output. The current representation preserves raw3 at review1 and restores raw4 at review19 as a second existing context, never NEW. Strict GOA matching alone does not verify assignedBy or extension identity, so the evidence file retains the explicit joins. Genuine acquisition is complete; the original 19-row seed remains unchanged in provenance. All 20 original records join the actual 16-column export, seed and restored review.
The complete earlier review and journal remain preserved at the immutable original review and journal. All 30 historical quotation associations are retained separately. Exact quotation does not validate every old quote-to-claim interpretation. The current review has ten short excerpt occurrences: six row excerpts, three quoted core anchors and one shared UniProt catalytic-reaction finding; the guide and new journal prose do not repeat their quotation text.
The actual PTHR15172 tree has 68 nodes and 35 leaves; the alignment has 1,038 columns. Human AN16/PTN002495607 exactly matches the current 685-residue sequence. All three IBA origins are AN0/PTN001032282, on the actual target path. Later retained activity and lysosome IBDs add a zebrafish donor relative to the incoming records; the original versions remain literal. Self-donors reflect experimental grounding and are not circular evidence.
The current mouse P54818 donor chain includes positive cDNA-expression evidence: normal mouse cDNA raises activity in COS1 cells while the twitcher nonsense construct does not (PMID:8769874(https://pubmed.ncbi.nlm.nih.gov/8769874/)). A SapA-mutant experiment supports dependence of galactosylceramide degradation on its activator, and a twitcher mass-spectrometry study measures psychosine accumulation (PMID:11371512(https://pubmed.ncbi.nlm.nih.gov/11371512/), PMID:11734583(https://pubmed.ncbi.nlm.nih.gov/11734583/)). Authentic abstracts were read; individual full-paper GALC assay panels were not inspected. These donor scopes complement independent human evidence rather than replace it.
Official pathway R-HSA-9840310 contains reaction R-HSA-1606564, whose catalyst 1606568 leads to entity 1606575 and UniProt P54803, residues 43–685, in lysosomal lumen. The reaction's output 1605745 resolves to CHEBI:4167 D-glucopyranose, although its own catalyst definition specifies D-galactose. The small-molecule output discrepancy is recorded without altering the model, original galactose context, protein identity or compartment assertion. The compact evidence preserves the exact official object fields and retrieval hashes; the full responses remain in private provenance.
The immutable UniProt FUNCTION paragraph calls the linkage an ester bond, whereas its catalytic reaction and the GALC-SapA account identify glycosidic hydrolysis. A structured WRONG_STATEMENT/CHECK on the UniProt reference records the complete offending sentence. The complete psychosine reaction is quoted once as a readable unfolded finding, with the same RHEA identifier in its statement. The short pH excerpt directly anchors the acidic core setting. Section metadata occurs only beside an actual quote. No source cache is silently repaired, and the inferred cause remains unknown.
The individual manual reference assessments distinguish direct human experiments, mouse mechanistic studies, curated model membership, variant reports and large sequence surveys. A full-cache flag records availability, not that every section or figure was read. The actual 33-source union comprises 14 unchanged main sources and 19 native missing-only publication acquisitions. Native titles and availability headers are reconciled separately from reading scope, and all ten current excerpts match the normal caches using the repository’s UniProt continuation normalization where needed. New full caches for PMID:20886637 and PMID:34449528 do not imply their complete contents were inspected; those manual judgments retain the authentic abstract scope. PMID:8940268 remains abstract-only after documented restricted-access fallback failures. Target validation passed with zero curation advisories, strict GOA matching passed for all 20 original contexts, and computed status remains COMPLETE. The genuine EDIT history, private render/link checks and scoped whitespace checks passed. All 33 scientific source bytes and the derived term caches remain unchanged. No annotation action or term changed.
The glycosphingolipid degradation module provides related pathway context. Its GALC step cites the GALC review and the same Reactome reaction, so it is not counted as an independent experiment or independent evidence for psychosine hydrolysis.