L-ascorbate degradation KEGG:map00053 L-ascorbic acid degradation KEGG:map01100 GO:0019854 pathway KEGG:map00040 PMID:12644495 vitamin C degradation PMID:14996803 UPa:UPA00263 Degradation of L-ascorbic acid (vitamin C). The three gene ulaABC (formerly known as sgaTBA) encode the three components of the L-ascorbate phosphotransferase transport system (UlaABC). They are involved in the uptake and phosphorylation of L-ascorbate [PMID:12644495. Intracellular L-ascorbate-6-P is then transformed by L-ascorbate-6-P lactonase into 3-keto-L-gulonate-6-P. It has been proposed that this compound is decarboxylated by UlaD to L-xylulose-5-P, which is then converted to D-xylulose-5-P by the sequential actions of UlaE (encoding 3-epimerase activity) and UlaF (encoding 4-epimerase activity). carbohydrate degradation cofactor degradation