Sequestration of arginine by polyphosphate in vacuoles of yeast (Saccharomyces cerevisiae)

The conditions for synthesis, purification, and properties of tryptophanase by a marine organism (Vibrio K-7) were studied. Tryptophanase was induced by tryptophan and its analogs, and partially repressed by 0.5% glucose or glycerol. NaCl (0.4M) was required for optimal growth and tryptophanase activity in whole cells. The enzyme was purified to 92% homogeneity by heat treatment, hydroxyapatite chromatography and fractionation with ammonium sulfate. This tryptophanase has been found to have kinetic properties similar to the tryptophanase from other microorganisms. It carries out both , -elimination reactions (using tryptophan, serine, cysteine and S-methyl-cysteine as substrates) and -replacement reactions (forming tryptophan from indole and serine, cysteine or S-methyl-cysteine). The enzyme has a sedimentation coefficient of 9.2S and requires pyridoxal 5-phosphate as a cofactor. The optimal pH for the tryptophanase reaction is pH 8.0.Nonstandard Abbreviations PLP pyridoxal 5-phosphate - TPase tryptophanase - TSase tryptophan synthase - DHase dehydratase - TCA tricarboxylic acid - BSA bovine serum albumin Preliminary reports of this work have been presented (M. J. Klug and R. D. DeMoss, Bacteriol. Proc. 1971, p. 132; D. D. Whitt and R. D. DeMoss, Abstr. Annu. Meet. Am. Soc. Microbiol. 1973, p. 148)