7alpha-hydroxysteroid dehydrogenase explained

7-alpha-hydroxysteroid dehydrogenase
Ec Number:	1.1.1.159
Cas Number:	39361-64-3
Go Code:	0008709

In enzymology, a 7alpha-hydroxysteroid dehydrogenase is an enzyme that catalyzes the chemical reaction

3alpha,7alpha,12alpha-trihydroxy-5beta-cholanate + NAD⁺

\rightleftharpoons 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholanate + NADH + H⁺

Thus, the two substrates of this enzyme are 3alpha,7alpha,12alpha-trihydroxy-5beta-cholanate and NAD⁺, whereas its 3 products are 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholanate, NADH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is 7alpha-hydroxysteroid:NAD⁺ 7-oxidoreductase. Other names in common use include 7alpha-hydroxy steroid dehydrogenase, and 7alpha-HSDH.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes,, and .

References

• Haslewood ES, Haslewood GA . The specificity of a 7 alpha-hydroxy steroid dehydrogenase from Escherichia coli . The Biochemical Journal . 157 . 1 . 207–10 . July 1976 . 10.1042/bj1570207 . 786279 . 1163832 .
• MacDonald IA, Roach PD . Bile induction of 7 alpha- and 7 beta-hydroxysteroid dehydrogenases in Clostridium absonum . Biochimica et Biophysica Acta . 665 . 2 . 262–9 . August 1981 . 6945134 . 10.1016/0005-2760(81)90011-4 .
• Macdonald IA, Williams CN, Mahony DE . 7Alpha-hydroxysteroid dehydrogenase from Escherichia coli B: preliminary studies . Biochimica et Biophysica Acta (BBA) - Enzymology . 309 . 2 . 243–53 . June 1973 . 4581498 . 10.1016/0005-2744(73)90022-3 .
• Macdonald IA, Williams CN, Mahony DE, Christie WM . NAD- and NADP-dependent 7alpha-hydroxysteroid dehydrogenases from bacteroides fragilis . Biochimica et Biophysica Acta (BBA) - Enzymology . 384 . 1 . 12–24 . March 1975 . 236764 . 10.1016/0005-2744(75)90091-1 .