Atypical regioselective biohydrolysis on steroidal oxiranes by Aspergillus niger whole cells: Some stereochemical features

FABRICIO R. BISOGNO; ALEJANDRO A. ORDEN; CELESTE AGUIRRE PRANZONI; DIEGO A. CIFUENTE; OSCAR S. GIORDANO; MARCELA KURINA-SANZ

STEROIDS

ELSEVIER SCIENCE INC

Año: 2007 vol. 72 p. 643 - 652

0039-128X

5,6-Epoxycholestan-3beta-ol derivatives were hydrolyzed in a diastereoconvergent 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 alfa and beta 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 11394. These strains displayed opposite regioselectivity toward each isomer in an alfa and beta 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 11394. These strains displayed opposite regioselectivity toward each isomer in an alfa and beta 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. Aspergillus niger, particularly A. niger ATCC 11394. These strains displayed opposite regioselectivity toward each isomer in an alfa and beta 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. alfa and beta 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 oxiranes butwere 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. 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. this kind of steroidal oxiranes as substrates. this kind of steroidal oxiranes as substrates. A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates.