抄録
The method of the determination of a base exchange ability of thiaminase I which exchanges thiazole in the molecule of thiamine with pyridine was investigated using crude or partially purified thiaminase I of Bacillus thiaminolyticus. It was recognized that the amounts (0-1.0 μmoles) of heteropyrithiamine, a pyridine exchange product of thiamine, and the extinction coefficient at 386 mμ were relative when heteropyrithiamine was oxidized with alkaline ferricyanide after destroying thiamine (0.75 μmoles supposed to be present in a reaction mixture) by alkali. It was also observed that concentration of the acetone preparation of thiaminase was related with amounts of heteropyrithiamine produced to 5 μmoles. The optimum conditions of the base exchange reaction of the acetone preparation were pH 6.5 and 30℃ when the above method was applied. The examples of the specific activities at each step of the purification were shown by this method.
