Regioselective reduction of a steroid in a reversed micellar system with enzymatic NADH-regeneration

Hidehiko Hirakawa, Noriho Kamiya, Tsuyoshi Yata, Teruyuki Nagamune

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The regioselective reduction of androstandione to androsterone by 3α-hydroxysteroid dehydrogenase (HSDH) from Pseudomonas testosteroni was coupled to a cofactor (NADH) regeneration system with the oxidation of ethanol by yeast alcohol dehydrogenase (YADH) in sodium dioctyl sulfosuccinate (AOT)/isooctane reversed micelles. Each reaction was dominated by the system's water content (W0 = [H2O]/[AOT]). The catalytic activity of YADH increased monotonically with W0, whereas HSDH showed bell-shaped dependency on W0. Using a reversed micellar system increased stability of both enzymes in comparison with an aqueous system and prolonged NADH-regeneration; namely, a seven-fold increase in the total turnover number of NADH was achieved. These results suggest that the reversed micellar system is a promising choice for conjugate enzymatic reactions with dehydrogenases in a nonaqueous media.

Original languageEnglish
Pages (from-to)35-40
Number of pages6
JournalBiochemical Engineering Journal
Issue number1
Publication statusPublished - Oct 2003

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Environmental Engineering
  • Bioengineering
  • Biomedical Engineering


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