Abstract
In the previous papers, it was reported that L-ascorbic acid decomposing enzymes of bacteria were produced adaptively only in the cells grown in a medium containing L-ascorbic acid, but not in the unadapted cells even when they were in contact with L-ascorbic acid for a long time. In this paper, it was shown that the unadapted cells became able to metabolize L-ascorbic acid when a small quantity of glucose and casein hydrolyzate were given. Both D-araboascorbic acid and D-glucoascorbic acid too were decomposed by L-ascorbic acid decomposing cells, but other reductones such as reductic acid, dihydroxymaleic acid, and 5-methyl-3,4-dihydroxytetrone were not. On the other hand, some properties of L-ascorbic acid oxidase found in the unadapted cells were studied. Its optimum pH was about 5.0 and the optimum concentration of the substrate was 800μM. It was found, too, that endiol compounds such as D-araboascorbic acid, reductic acid and 5-methyl-3,4-dihydroxytetrone, etc. were not decomposed by this enzyme.
