抄録
In the previous paper, it was presumed that one of the pathways of L-ascorbic acid metabolism might be carried through dehydroascorbic acid and diketo-L-gluconic acid. In this paper this pathway was studied more precisely. Glyoxal, glyoxlic acid and mesoxalic acid were not decomposed by L-ascorbic acid decomposing cells. Both dehydroascorbic acid and D-arabinosone were metabolized not by unadapted cells, but by L-ascorbic acid adapted cells slowly, and the latter metabolic rate was acceralated when a small quantity of glucose or L-ascorbic acid was added as hydrogen donators. From the finding that the volume of O_2 uptake for DL-glyceraldehyde (15μM) by L-ascorbic acid adapted cells was about half that of D-glyceraldehyde (15μM), it was presumed that perhaps L-glyceraldehyde was not metabolized. From the results above mentioned, the course via dehydroascorbic acid was presumed as follows : L-Ascorbic acid→dehydroascorbic acid→diketo-L-gulonic acid→(L-xylosone)→D-arabinosone→D-ribose.
