Tryptophanase from a marine bacterium, Vibrio K-7 synthesis, purification, and some chemical catalytic properties

Abstract

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 (0.4 M) 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 alpha, beta-elimination reactions (using tryptophan, serine, cysteine and S-methylcysteine as substrates) and beta-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.

Photoproduction of L‐tryptophan from indole and glycine by Rhodobacter sphaeroides OU5

“…The widely used precursors for Ltryptophan synthesis are indole and L-serine [13,14], and the process is catalysed by the enzyme tryptophan synthase [15]. Alternatively, L-tryptophan is synthesized by the action of tryptophanase [16] catalysing L-tryptophan synthesis from indole, pyruvate and NH 4 Cl [17]. Microbial production of L-tryptophan using precursors can be very efficient and economically viable with organisms that efficiently biotransform the precursor to the product without using them for their normal growth and energy requirements.…”