Enzymatic preparation of d- p -trimethylsilylphenylalanine.

In this paper we report on the enzymatic preparation of d- p-trimethylsilylphenylalanine ( d-TMS-Phe). First, dl-5-( p-trimethylsilylphenylmethyl)hydantoin␣( dl-TMS-Phe-Hyd) was synthesized chemically and subjected to bacterial hydrolysis to obtain N-carbamoyl- d- p-trimethylsilylphenylalanine (C- d-TMS-Phe), but no strains examined showed sufficient hydantoinase activity on this compound. However, Blastobacter sp. A17p-4, which is known to produce N-carbamoyl- d-amino acid amidohydrolase (DCase), was found to be able to hydrolyze C- dl-TMS-Phe prepared chemically from the hydantoin. When C- dl-TMS-Phe was hydrolyzed with cells of Blastobacter sp. A17p-4, its optical purity was low because N-carbamoyl- l-amino acid amidohydrolase (LCase) coexisted in the cells. DCase and LCase in the cell-free extract of Blastobacter sp. A17p-4 could be separated by DEAE-Sephacel column chromatography. The optimum pH for the hydrolysis of C- dl-TMS-Phe by the partially purified DCase was 8.0 and addition of 2.5 % N, N-dimethylformamide was effective in raising the substrate concentration without inactivation of DCase. Under the optimized conditions, highly optically pure (98 % enantiomeric excess) d-TMS-Phe could be obtained from C- dl-TMS-Phe with partially purified DCase. [ABSTRACT FROM AUTHOR]