Studies in the Enzyme Make-up of Vibrio cholerae: Part XIII-Tryptophanase Activity of Vibrios

Abstract

The distribution of tryptophanase in various cholertgenic and non-cholertgenlc strains of vibrios, and the optimum conditions for the extraction of the enzyme in cell-free state have been described. The properties of the enzyme and the action of enzyme inhibitors and coenzymes on it have also been studied. Incorporation of sodium and potassium chlorides in the growth medium has been found to stimulate the production of the enzyme by the cells, and potassium chloride solution has been found to be relatively specific for the extraction of the enzyme from viable cells. Indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and acetyl DL-tryptophane are not decomposed by the enzyme and they do not affect the normal course of tryptophane breakdown by the enzyme. Cyanide, hydrazine and hydroxylamine, copper and mercury salts in very small concentrations inhibit the activity of the enzyme completely. Compounds having sulphydryl groups also strongly inhibit the activity of the enzyme; glutathione is more powerful than' cysteine. Pyridoxal phosphate has been found to activate tryptophanase of V. choleras, whereas diphosphopyridine nucleotide and riboflavin have no effect.