Regio- and stereospecific conversion of 4-alkylphenols by the covalent flavoprotein vanillyl-alcohol oxidase.
J Bacteriol
; 180(21): 5646-51, 1998 Nov.
Article
en En
| MEDLINE
| ID: mdl-9791114
The regio- and stereospecific conversion of prochiral 4-alkylphenols by the covalent flavoprotein vanillyl-alcohol oxidase was investigated. The enzyme was active, with 4-alkylphenols bearing aliphatic side chains of up to seven carbon atoms. Optimal catalytic efficiency occurred with 4-ethylphenol and 4-n-propylphenols. These short-chain 4-alkylphenols are stereoselectively hydroxylated to the corresponding (R)-1-(4'-hydroxyphenyl)alcohols (F. P. Drijfhout, M. W. Fraaije, H. Jongejan, W. J. H. van Berkel, and M. C. R. Franssen, Biotechnol. Bioeng. 59:171-177, 1998). (S)-1-(4'-Hydroxyphenyl)ethanol was found to be a far better substrate than (R)-1-(4'-hydroxyphenyl)ethanol, explaining why during the enzymatic conversion of 4-ethylphenol nearly no 4-hydroxyacetophenone is formed. Medium-chain 4-alkylphenols were exclusively converted by vanillyl-alcohol oxidase to the corresponding 1-(4'-hydroxyphenyl)alkenes. The relative cis-trans stereochemistry of these reactions was strongly dependent on the nature of the alkyl side chain. The enzymatic conversion of 4-sec-butylphenol resulted in two (4'-hydroxyphenyl)-sec-butene isomers with identical masses but different fragmentation patterns. We conclude that the water accessibility of the enzyme active site and the orientation of the hydrophobic alkyl side chain of the substrate are of major importance in determining the regiospecific and stereochemical outcome of vanillyl-alcohol oxidase-mediated conversions of 4-alkylphenols.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Penicillium
/
Fenoles
/
Oxidorreductasas de Alcohol
/
Flavoproteínas
Idioma:
En
Revista:
J Bacteriol
Año:
1998
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Estados Unidos