INTEQUI   20941
INSTITUTO DE INVESTIGACIONES EN TECNOLOGIA QUIMICA
Unidad Ejecutora - UE
artículos
Título:
Atypical regioselective biohydrolysis on steroidal oxiranes by Aspergillus niger whole cells:
Autor/es:
FABRICIO R. BISOGNO; ALEJANDRO A. ORDEN; CELESTE AGUIRRE PRANZONI; DIEGO A. CIFUENTE; OSCAR S. GIORDANO; MARCELA KURINA SANZ
Revista:
STEROIDS
Editorial:
ELSEVIER
Referencias:
Año: 2007 vol. 72 p. 642 - 652
ISSN:
0039-128X
Resumen:
5,6-epoxycholestan-3ƒÒ-ol derivatives were hydrolyzed in a diasteroconvergent manner by growing and resting cells of several strains of  Aspergillus niger,  particularly A. niger ATCC 11394. These strains displayed opposite regioselectivity toward each isomer in an ƒÑ and ƒÒ epoxide mixture, thus, the nucleophilic attack took place at the less substituted and the most substituted carbon atom on each diasteromer, respectively. These biocatalysts opened trisubstituted oxirane but were unable to hydrolyze the disubstituted oxiranes in the tested sterol derivatives. These findings suggest that A. niger strains possess another hydrolytic ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates.