Membrane-bound dehydrogenases of Pseudomonas testosteroni

Abstract

Abstract During uptake of testosterone by membrane vesicles prepared from Pseudomonas testosteroni , NADH produced by 3β- and 17β-hydroxy steroid dehydrogenase is generated inside the vesicles. The membrane vesicles have been shown to possess an NADH dehydrogenase which appears to be located on the inner face of vesicle membranes and of whole cell cytoplasmic membranes. This suggests that the orientation of the membrane vesicles is the same as the cells from which they were derived. A membrane-bound 1-ene-dehydrogenase activity has also been demonstrated. 1-ene-Dehydrogenase activity of membrane vesicles was demonstrable both in the presence and absence of NAD + . In the absence of NAD + , testosterone was converted to 1-dehydrotestosterone. In the presence of NAD + testosterone was converted initially to androstenedione by 3β- and 17β-hydroxysteroid dehydrogenase activity and subsequently dehydrogenated to 1,4-androstadiendione.