A New Method for the Production of Optically Active Aminoacids
This paper illustrates a new method for the preparation of optically active amino acids which consists of the chemical synthesis of a racemic compound, its enzymic transformation into one of the two optical isomers and finally the hydrolysis of this intermediate to yield the optically active amino acid. The biological procedures currently used for the resolution of the amino acid racemates are based on the action of microorganisms or enzymes which preferentially attack one of the two optical isomers or its derivatives. For example, the asymmetric oxidation or decarboxylation of amino acids in which one isomer is transformed to a ketoacid or an amine while the other isomer is unaffected. The use of oxidases or decarboxylases has some disadvantages: 1) it results in the degradation of one isomer the product of which is difficult to recycle; 2) this degra-dation must be complete, otherwise the optical purity of the unaffected isomer is poor. Another resolution method which is used extensively consists of the hydrolysis of one isomer of an amino acid derivative (e.g. the action of acylase on N-acetyl amino acids). However, the use of acylase, esterase or amidase also has drawbacks, primarily being the requirement of an efficient method for the separation of the optically active product from the derivative which is not hydrolyzed. The latter can be chemically racemized and recycled but the racemization occurs generally under severe conditions which decrease the yield.
KeywordsOptical Isomer Biological Procedure Active Amino Acid Amino Acid Racemate Asymmetric Oxidation
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