Abstract
In order to investigate a possibility that S-carbalkoxythiamine (CAT) hydrolyzing enzyme may be identical with a known non-specific esterase such as aliesterase or cholinesterase, both activities being found in the partially purified liver extract, the characters of these three hydrolase activities have been compared with one another. As each hydrolase activity in the crude extract was increased to different degrees after purification by a same procedure, and effects of neostigmine, cupric ion and rivanol treatment on each activity were not similar, it was suggested that CAT hydrolyzing enzyme is different from such esterases. CAT hydrolyzing enzyme was shown to be able to hydrolyze S-acyl-thiamine derivatives, but it was also demonstrated that liver contained an another S-acylthiamine hydrolyzing enzyme which could be separated from CAT hydrolyzing enzyme by treating the homogenate with ethylene dichloride and showed no activity toward CAT.
