Screening of an enzyme which can promote the asymmetric decarboxylation of a-aryl-a-methylmalonic acids was carried out as follows. Microorganisms that can grow on a medium containing phenylmalonic acid as the sole source of carbon was screened, supposing that the first step of the major metabolic path of the acid is decarboxylation to give phenylacetic acid, which would be further metabolized. At least a part of the enzymes are expected to be also active to the compounds with a methyl on the a-position as the structural difference is not so serious. The presence of a methyl group is expected to conveniently inhibit the following oxidative metabolic degradation, resulting in the formation of optically active a-arylpropionic acid. Thus, a wide variety of soil samples and type cultures were tested and a few strains were found which grew on the medium. Among them, a bacterium identified as Alcaligenes bronchisepticus KU1201, resulted in optically active a-arylpropionic acid starting from a-aryl-a-methylmalonate as shown in Table 1.8
Asymmetric decarboxylation of arylmethymalonate catalyzed by A. bronchisepticus
A. bronchisepticus hi
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