Synthesis of D-cysteine-related amino acids by 3-chloro-D-alanine chloride-lyase of Pseudomonas putida CR 1-1

Physiological comparison of D-cysteine desulfhydrase of Escherichia coli with 3-chloro-D-alanine dehydrochlorinase of Pseudomonas putida CR 1-1

D-Cysteine desulfhydrase of Escherichia coli W3110 delta trpED102/F' delta trpED102 was physiologically characterized. It was found to be located in the cytosolic fraction, as 3-chloro-D-alanine dehydrochlorinase is. D-Cysteine desulfhydrase catalyzed not only the alpha, beta-elimination reaction of O-acetyl-D-serine to form pyruvate, acetic acid and ammonia, but also the beta-replacement reaction of O-acetyl-D-serine with sulfide to form D-cysteine. However, these reactions appeared not to proceed in vivo. No other activity of D-cysteine synthesis from O-acetyl-D-serine and sulfide was detected in a crude cell extract of E. coli which was immunotitrated with antibodies raised against the purified D-cysteine desulfhydrase. Although D-cysteine desulfhydrase catalyzes the degradation (alpha, beta-elimination reaction) of 3-chloro-D-alanine, which is an effective antibacterial agent, E. coli W3110 delta trpED102/F' delta trpED102 did not show resistance against 3-chloro-D-alanine. Therefore, D-cysteine desulfhydrase does not contribute to 3-chloro-D-alanine detoxification in vivo.

Enzymatic transformations of 3-chloroalanine into useful amino acids

The investigation of the combination of enzymatic and chemical synthetic processes for the production of useful compounds has been carried out. This review focuses on the enzymatic transformation of chemically synthesized 3-chloroalanine into useful amino acids.

D-Cysteine desulfhydrase of Escherichia coli. Purification and characterization

D-Cysteine-specific desulfhydrase is found in some intestinal bacteria. Escherichia coli W3110 delta trpED102/F' delta trpED102 was found to have the highest enzyme activity. The enzyme was purified from E. coli W3110 delta trpED102/F' delta trpED102 in six steps. After the last step the enzyme appeared to be homogeneous by the criteria of polyacrylamide gel electrophoresis, analytical ultracentrifugation and double diffusion in agarose. The enzyme has a molecular mass of about 67 000 Da and consists of two subunits identical in molecular mass. The enzyme exhibits absorption maxima at 278 nm and 418 nm, which are independent of pH (6.5-10.5), and contains 2 mol pyridoxal phosphate/mol enzyme. The holoenzyme is resolved to the apoenzyme by incubation with phenylhydrazine, and reconstituted on the addition of pyridoxal phosphate. D-Cysteine desulfhydrase also catalyzes the beta-replacement reaction of the chlorine of 3-chloro-D-alanine with thioglycolic acid to yield S-carboxymethyl-D-cysteine. Its catalytic and immunological properties are compared with those of 3-chloro-D-alanine dehydrochlorinase.

Fuels and industrial chemicals through biotechnology. 2

An overview of research on the biotechnical production of fuels and industrial chemicals during the two-year period of 1983-1984 is presented. Ethanol fermentation has continued to be the subject of major interest. A considerable amount of work has been directed to alternative feedstocks such as pentose sugars and lactose, and to bacterial fermentations. Reports on extrusion cooking as a continuous pretreatment method for subsequent ethanol fermentation, and on novel alternative downstream processing techniques have been published. In addition to ethanol fermentation, much attention has been paid to the biotechnical production of 2,3-butanediol, and of a number of organic and amino acids. In general, there appears to be a growing interest in the application of biocatalysis for the production of specialty chemicals, although only a few examples will be discussed in this paper. The construction of a demonstration plant to produce ethanol from molasses by a two 10 kL bed-volume immobilized yeast bioreactors at the Kyowa Hakko Kogyo Company Hofu plant, the announcement by Nitto Chemical Industries Company to begin the biotechnical production of acrylamide, and the French decision to construct pilot plants for the biotechnical production of acetone-butanol-ethanol cosolvent and of ethanol from renewable resources represent major scale-up developments.

Synthesis of S-(carboxymethyl)-D-cysteine by 3-chloro-D-alanine chloride-lyase of pseudomonas putida CR 1-1

S-(Carboxymethyl)-D-cysteine, which is an important component of semisynthetic cephalosporin, MT-141, was enzymatically synthesized. S-(Ethoxy-carbonyl-methyl)-D-cystein was synthesized from 3-chloro- D-alanine and ethyl thioglycolate by the beta-replacement reaction of 3-chloro-D-alanine chloride-lyase from Pseudomonas putida CR 1-1 and subsequently hydrolyzed by alkali. The synthesized S-(carboxymethyl)-D-cysteine was isolated from a large scale reaction mixture and identified physicochemically. The reaction conditions for the synthesis of S-(ethoxycarbonylmethyl)-D-cysteine were optimized using resting cells of P. putida CR 1-1.