Xenopus laevis uap1.S encodes a UDP-N-acetylhexosamine pyrophosphorylase that is predicted to convert UTP and N-acetylglucosamine-1-phosphate to UDP-N-acetylglucosamine. This reaction supplies an activated sugar nucleotide for cellular glycosylation pathways. The complete UAP-like architecture and conserved nucleotide-sugar contacts support the assignment; the relative GlcNAc and GalNAc substrate preferences of the frog protein have not been measured.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003977 UDP-N-acetylglucosamine diphosphorylase activity | IEA GO_REF:0000118 | ACCEPT | Summary: The complete UAP1-like sequence preserves the annotated human nucleotide-sugar contacts, and recombinant human/fungal orthologs establish UDP-GlcNAc pyrophosphorylase activity. This supports the specific reaction as an evolutionary inference for the frog product. Supporting Evidence: PMID:9603950 All the recombinant ScUap1p, CaUap1p, and HsUap1p possessed UDP-N-acetylglucosamine pyrophosphorylase activities in vitro. PMID:9603950 The yeast Uap1p utilized N-acetylglucosamine-1-phosphate as the substrate file:XENLA/uap1.S/uap1.S-bioinformatics/RESULTS.md | 1–453 | 1–453 | 342 | |
| GO:0006048 UDP-N-acetylglucosamine biosynthetic process | IEA GO_REF:0000118 | ACCEPT | Summary: Producing UDP-GlcNAc from GlcNAc-1-phosphate and UTP directly contributes to UDP-GlcNAc biosynthesis. The intact UAP-like sequence supports this reaction-level pathway annotation without assigning every downstream glycosylation process. Supporting Evidence: PMID:9603950 All the recombinant ScUap1p, CaUap1p, and HsUap1p possessed UDP-N-acetylglucosamine pyrophosphorylase activities in vitro. PMID:9603950 The yeast Uap1p utilized N-acetylglucosamine-1-phosphate as the substrate file:XENLA/uap1.S/uap1.S-bioinformatics/RESULTS.md | 1–453 | 1–453 | 342 | |
| GO:0070569 uridylyltransferase activity | IEA GO_REF:0000120 | MODIFY | Summary: Uridylyltransferase activity is correct but broader than the sequence-supported UAP1 substrate-specific reaction. Use UDP-N-acetylglucosamine diphosphorylase activity. Proposed replacements: UDP-N-acetylglucosamine diphosphorylase activity Supporting Evidence: PMID:9603950 All the recombinant ScUap1p, CaUap1p, and HsUap1p possessed UDP-N-acetylglucosamine pyrophosphorylase activities in vitro. file:XENLA/uap1.S/uap1.S-bioinformatics/RESULTS.md | 1–453 | 1–453 | 342 | |
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