抄録
Previous studies from this laboratory have established that the alkaloid berberine inhibits two typical vitamin B6-enzymes of bacterial origins, i. e. tyrosine decarboxylase of Streptococcus faecalis and tryptophanase of Escherichia coli. Evidence has also been reported to indicate that berberine inhibits these enzymes by competing with the coenzyme pyridoxal phosphate. It has further been shown that the alkaloid, once combined with the apoenzymes, causes slow and irreversible inactivation of the enzymes.
The present investigation was undertaken to examine if berberine behaves similarly toward pig heart glutamic-aspartic transaminase, a typical B6-enzyme of mammalian tissues. The results obtained were, however, rather contrary to expectation; no inhibition by berberine could be observed in spite of many attempts. It appears, therefore, that the susceptibility of the mammalian 6 enzyme is significantly different from that of bacterial 6 enzymes for reasons to be elucidated in future.
