Enzymatic conversion of racemic methionine to the L-enantiomer

Abstract

We have developed an enzymatic method for conversion of racemic methionine to the L-enantiomer with a yield of >95% and >99% enantiomeric excess; the method has been applied to the conversion of DL-alanine and m-leucine to the L-enantiomers.Racemic amino acids may be resolved to their L-and D-enantiomers by enzymatic or chemical procedures.1 No methods, however, are available for a total conversion of the racemate to only one enantiomer. L-Methionine is used widely as a feed additive, a component of infusion, and a starting material for pharmaceutical synthesis, but microbial methods have not been developed for L-methionine production. We here describe a simple method for the production of Lmethionine from the racemate by means of D-amino acid oxidase (EC 1.4.3.3), catalase (EC 1.11.1.6), leucine dehydrogenase (EC 1.4.1.9), and formate dehydrogenase (EC 1.2.1.2), D-Methionhe is fully converted to the L-enantiomer in situ through an achiral intermediate, a-oxo-y-methylthiobutyrate, in an enzymatic system containing oxygen, NAD+, and ammonium formate (Scheme 1). L-Methionine 1 NADH NAD+ H20 b CO;! HCOF Scheme 1. Reaction scheme for the enzymatic conversion of DLmethionine to the L-enantiomer: a, D-amino acid oxidase; b, catalase; c, leucine dehydrogenase; d, formate dehydrogenase.

From a Racemate to a Single Enantiomer: Deracemization by Stereoinversion

“…[104] Aiming at the development of more efficient whole-cell biocatalysts, deracemization of 4-chlorophenylalanine was reported using a 'designer bug,' i.e., Escherichia coli cells expressing an l-amino acid aminotransferase from Sinorhizobium meliloti ATCC 51124. The enantiopure l-a-amino acid was obtained in high optical yield via the tandem action of d-amino acid dehydrogenase from the E. coli host cell (induced by l-alanine in the medium), and the cloned lamino acid aminotransferase from Sinorhizobium meliloti.…”

Biotransformation of D‐methionine into L‐methionine in the cascade of four enzymes

“…Besides two-enzyme systems, three-enzyme and fourenzyme systems are represented as well (Bae et al, 1999;Galkin et al, 1997;Hanson et al, 1992;Nakajima et al, 1990a,b;Soda et al, 2001;Yun et al, 2003). Several scientists studied such systems in which they used various enzyme combinations (Bae et al, 1999;Galkin et al, 1997;Nakajima et al, 1990b;Soda et al, 2001). In one article, Soda and co-workers (Soda et al, 2001) combined the action of D-amino acid aminotransferase, glutamate racemase, glutamate dehydrogenase, and FDH to obtain optically pure D-phenylalanine and D-tyrosine (Bae et al, 1999) without the additional by-products.…”

Multi‐Enzymatic Cascade Reactions: Overview and Perspectives

“…[61] Cofactor regeneration for the latter enzyme was supplied by formate dehydrogenase (FDH). Furthermore, catalase was added for hydrogen peroxide degradation in order to prevent oxidative enzyme inactivation (Scheme 11).…”