Enzymatic Determination of Bile Acids. The Presence of a New Enzyme, a 12α-Hydroxysteroid: NAD-oxidoreductase in Extracts fromPseudomonas testosteroni

Skålhegg, B. A. Enzymatic determination of bile acids. The presence of a new enzyme, a 12a-hydroxysteroid: NAD-oxidoreductase in extracts from Pseudomonas testosteroni. Scand. J. Gastroent. 1974, 9, 555–557.By use of a specific substrate (5β-choIanic acid-3α, 7α, 12α-triol-3,7-diacetatemethyl ester), crude preparations of 3α-hydroxysteroid dehydrogenase (3α-HSD) from Pseudomonas testosteroni have been shown to exhibit 12a-hydrox-ysteroid dehydrogenase (12α-HSD)-activity. The two hydroxysteroid dehydrogenase activities seem to be caused by different enzymes, since no 12α-HSD activity could be detected in a purified preparation of the 3α-HSD. Both enzymes are NAD specific. The 12α-HSD will influence the enzyme assay for 3α-hydroxy bile acids, since such measurements are usually performed with crude extracts of P. testosteroni.