Catalyzes the first step in hexosamine metabolism, converting fructose-6P into glucosamine-6P using glutamine as a nitrogen source
Original wording and all model/source metadata are retained in Gfat1-protnlm-source.json.
NPI for the complete glutamine-dependent catalytic reaction. The model assigns conversion of fructose-6-phosphate using glutamine as nitrogen donor to Gfat1-PF. The exact target is a native 434-residue isoform matching the C-terminal region of full-length Gfat1, and lacks the catalytic cysteine and most of the glutaminase module. The retained SIS region cannot itself extract nitrogen from glutamine. This is an isoform-scope error, not proof of a wrong input sequence or absence of every possible regulatory/sugar-binding function.
The reproducible alignment maps the missing domain. PMID:16339762(https://pubmed.ncbi.nlm.nih.gov/16339762/) establishes the coupled glutaminase/synthase mechanism; PMID:19059404(https://pubmed.ncbi.nlm.nih.gov/19059404/) demonstrates ligand-bound isolated human isomerase domains and supports retention of binding without assuming the full reaction. Bacterial donor Q8KG38 and model score 0.96 are preserved in the original source JSON.