Abstract
1) In the lumen of rat small intestine, D-glucurono lactone was converted to l-ascorbic acid, and this was promoted by the presence of SH compounds, such as glutathionine (GSH) or cysteine, but inhibited by P-chloromercuri benzoate (PCMB), NaAsO2, or CH, ICOOH.
2) In the case of ascorbic acid formation from d-glucose, Robinson-ester, or Harden Young-ester neither of SH compounds nor their inhibitors were observed to have this effect.
3) Yet the biosynthesis of l-ascorbic acid from Cori-ester was conspicuously accelerated by oxidized glutathione (GSSG) or PCMB, and inhibited by GSH and cysteine.
4) These results suggest us that the phosphorylation of D-glucose to Cori-ester is the first and direct pathway of the biosynthesis of l-ascorbic acid from D-glucose in intestine.
