Portal de Periódicos da CAPES

Capítulo de livro Produção Nacional Revisado por pares

BIBTEX RIS

Effects of Temperature on Stereochemistry of Alcohol Dehydrogenases from Thermoanaerobacter ethanolicus

1992; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-444-89046-7.50044-8

2212-117X

Robert S. Phillips, Viet Van Pham, Changsheng Zheng, Francisco A.C. Andrade, Maria A.C. Andrade,

Amino Acid Enzymes and Metabolism

Abstract We have studied the effects of temperature on the stereochemistry of NADP-dependent primary (PADH) and secondary (SADH) alcohol dehydrogenases from the thermophilic bacterium, Thermoanaerobacter ethanolicus. Reduction of 1% 2-butanone with SADH in 10% 2-propanol gives (R)-2-butanone, with increased stereoselectivity at high temperature and in the presence of NADP analogues. Reduction of 2-pentanone under the same conditions gives (S)-2-pentanol, with decreased stereoselectivity at high temperatures and in the presence of NADP analogues. Reduction of racemic 2-methylbutyraldehyde by PADH gives (S)-2-methyl-1-butanol, with the stereochemical purity increasing from 14% e.e. at 15° to 51% e.e. at 35°. These results show that optimal stereoselectivity in an enzymatic reaction may sometimes be obtained at the highest temperature compatible with the stability of the enzyme substrate and cofactor system.