566-08-5Relevant articles and documents
Microbial transformation of androstenedione by Cladosporium sphaerospermum and Ulocladium chartarum
Yildirim, Kudret,Kuru, Ali,Kü?ükba?ol, Eda
, p. 7 - 14 (2019/05/15)
In this work, incubations of androstenedione 1 with Cladosporium sphaerospermum MRC 70266 and Ulocladium chartarum MRC 72584 have been reported. C. sphaerospermum MRC 70266 mainly hydroxylated 1 at C-6β, accompanied by a hydroxylation at C-15α, a reduction at C-17, a 5α-reduction and oxidations at C-6 and C-16 following hydroxylations. U. chartarum MRC 72584 hydroxylated 1 at C-6β, C-7α, C-7β and C-14α, accompanied by an oxidation at C-6 following its hydroxylation, a reduction at C-17 and a 5α-reduction. 6β,17β-Dihydroxyandrost-4-en-3,16-dione 8, one of the metabolites from the incubation of 1 with C. sphaerospermum MRC 70266, was determined as a new compound.
Escherichia coli expression of site-directed mutants of cytochrome P450 2B1 from six substrate recognition sites: Substrate specificity and inhibitor selectivity studies
You Qun He,You Ai He,Halpert
, p. 574 - 579 (2007/10/03)
Cytochrome P450 2B1 wild-type and eight site-directed mutations at positions 114, 206, 236, 302, 363, 367, and 478 have been expressed in an Escherichia coli system. Solubilized membrane preparations yielded 100-180 nmol of P450/L of culture. The metabolism of a number of substrates including androstenedione, progesterone, (benzyloxy)resorufin, pentoxyresorufin, and benzphetamine was analyzed. The E. coli-expressed enzymes displayed the same androstenedione metabolite profiles previously observed with a COS cell expression system. Several of the mutants exhibited an increased rate of progesterone hydroxylation, possibly as the result of an enlarged substrate binding pocket and increased D-ring α-face binding. (Benzyloxy)resorufin and pentoxyresorufin O-dealkylation by the P450 2B1 mutants exhibited activities ranging from 10% to 99% and 3% to 71% of wild-type, respectively. Interestingly, the Val-363 → Leu mutant showed markedly suppressed pentoxyresorufin but unaltered (benzyloxy)resorufin dealkylase activity. Benzphetamine N-demethylase activities ranged from 28% to 110% of wildtype. Mechanism-based inactivation of the P450 2B1 mutants showed that susceptibility to inactivation by chloramphenicol and D-erythro- and L- threo-chloramphenicol was abolished in the Val-367 → Ala mutant. The Val- 363 → Leu mutant was refractory to L-threo-chloramphenicol. Studies of chloramphenicol covalent binding and metabolism by the Val-367 → Ala mutant showed that its resistance to inactivation is largely attributable to an inability to bioactivate the inhibitor. The expression of P450 2B1 wild-type and mutants in E. coli provides an excellent opportunity to study structure/function relationships by site-directed mutagenesis.