1) In Part I, the present authors have reported biochemical studies on intermediary metabolism of vitamins concerning with the interaction of vitamin B1 and sulfhydryl group in protein molecules. Recently, further studies on these problems in vegetables have been attempted, and negative factors were tested in edible part of the vegetables. Since a few years ago, of special importance seems to be that many papers were published concerning with vitamin B1-decomposing enzyme, thiaminase, but on the contrary, few appeared from a view point of negative factors in intermediary metabolism of the vegetables.
2) In the present paper, further distribution of vitamin B1-decomposing enzyme, thiaminase, was studied. he results of the experiments with 50 γ vitamin B1 are as shown in Table 1_??_3. Several experiments were repeated by treating the raw material in boiling water at pH 5_??_8 for 2 mins., and it was confirmed that the activities in edible vegetables may be extremely diminished in the ordinary case.
