Abstract
It was found that berberine inhibits the tryptophanase system of Escherichia coli by competing with the coenzyme, pyridoxal phosphate, when acetone-dried cells or partially purified cell-free extracts were used as the enzyme. The inhibition was also found to be of irreversible nature. A mechanism was proposed to account for both the competitive and irreversible nature of the inhibition. Some kinetic considerations were made on the proposed mechanism. The inhibition of tryptophanase by berberine in intact cells was stronger than that in acetone-dried cells and it was inferred that different mechanisms are functioning in the inhibitions of the two types of cells.
