NAD-dependent 3alpha- And 12alpha-hydroxysteroid Dehydrogenase Activities From Eubacterium Lentum ATCC No. 25559

Biochim Biophys Acta. 1977 Dec 21;489(3):466-76. doi: 10.1016/0005-2760(77)90167-9.


Eubacterium lentum (ATCC No. 25559) was shown to contain 3alpha-and 12alpha-hydroxysteroid dehydrogenases both of which were NAD-dependent and active against conjugated and unconjugated bile salts. In addition, the 3alpha-hydroxysteroid dehydrogenase was active against members of the Androstan series containing a 3alpha-hydroxyl group regardless of the stereo-orientation of the 5-H-. No measurable activity against 7alpha-, 7beta-, 11beta-, or 17beta-hydroxyl groups was demonstrated. The growth of E. lentum and the production of 3alpha- and 12alpha-hydroxysteroid dehydrogenases were greatly enhanced by the addition of L-, D- or DL-arginine to the medium. Yields of hydroxysteroid dehydrogenase were optimal in the range of 0.50-0.75% arginine; however, the growth of the organisms was further enhanced at arginine concentrations greater than 0.75%. The 12alpha-hydroxysteroid dehydrogenase was heat labile and could be selectively inactivated by heating at 50 degrees C for 45 min. Both the heated enzyme preparation (containing only 3alpha-hydroxysteroid dehydrogenase) and the unheated enzyme preparation (containing 3alpha- and 12alpha-hydroxysteroid dehydrogenases) were useful in the spectrophotometric quantification of bile salts. The optimal pH values for 3alpha- and 12alpha-hydroxysteroid dehydrogenases were 11.3 and 10.2, respectively. Kinetic studies have Km estimates of 2.10(-5) M and 1.0.10(-4) M with 3alpha,7alpha-dihydroxy-5beta-cholanoyl glycine and 7alpha,12alpha-dihydroxy-5beta-cholanoate for the two respective enzymes.

MeSH terms

  • 3-Hydroxysteroid Dehydrogenases / metabolism*
  • Arginine / pharmacology
  • Bile Acids and Salts / pharmacology
  • Cell Division / drug effects
  • Enzyme Induction / drug effects
  • Eubacterium / enzymology*
  • Eubacterium / physiology
  • Hydroxysteroid Dehydrogenases / metabolism*
  • Kinetics
  • NAD


  • Bile Acids and Salts
  • NAD
  • Arginine
  • 3-Hydroxysteroid Dehydrogenases
  • Hydroxysteroid Dehydrogenases