抄録
It was found that thiamine was biosynthesized by green leaves from 2-methyl-4-amino-5-hydroxymethylpyrimidine pyrophosphate and thiazole phosphate or thiazole in the presence of MgCl_2. Some properties of the enzyme reaction were investigated with the homogenate of radish leaves. The enzyme had an optimum pH at around 9.0 and had the maximum activity at 30℃. The production of thiamine in the homogenate was inhibited abruptly after an elapse of the reaction for about 30 minutes, and then the vitamin formed was destroyed gradually. The destruction of the vitamin during the incubation was protected partly by the addition of mercaptoethanol.
