Enzymatic Production ofl-Cysteine fromdl-2-Amino-Δ2-thiazoline-4-carboxylic Acid byPseudomonas thiazolinophilum: Optimal Conditions for the Enzyme Formation and Enzymatic Reaction

Abstract

Cultural conditions of Ps. thiazolinophilum AJ 3854 for the production of the enzyme which could form l-cysteine from dl-2-amino-Δ2-thiazoline-4-carboxylic acid (ATC) and the reaction conditions of this enzyme were investigated. This enzyme was perfectly inducible, intracellular and growth-associated type. A remarkable inactivation of enzyme was observed especially in the growing phase but could be prevented by the addition of 1 ~ 10 mm Mn2+ or by the feeding of ATC as the inducer at the mid-logarithmic phase. Enzymatic degradation of l-cysteine (or l-cystine) formed from ATC could be prevented by the addition of hydroxylamine or semicarbazide. Thus, l-cysteine and l-cystine were quantitatively produced from ATC. Optimal pH and temperature of enzymatic reaction were 8.2 and 42°C (2hr), respectively. A sigmoidal reaction curve was observed when intact cells were used as enzyme source, but sonic treatment of cells made the curve linear.