Coupling between 3-ketosteroid-delta'-dehydrogenase and the respiratory chain in the bacterium Arthrobacter globiformis
Medentsev, A.G.; Arinbasarova, A.I.; Koshcheenko, K.A.; Akimenko, V.K.
Biokhimiia 48(10): 1726-1732
1983
ISSN/ISBN: 0320-9725 PMID: 6639991 Document Number: 213849
Intact bacterial cells and their cytoplasmic membranes obtained by ultrasonic desintegration are able to induce dehydration of hydrocortisone to prednisolone that is coupled with O2 uptake. This reaction is inhibited by cyanide and 2-n-nonyl-4-hydroxyquinoline-N-oxide (HOQNO). Oxidation of hydrocortisone results in cytochrome reduction both in intact cells and in cytoplasmic membranes. Aerobic dehydration of hydrocortisone is linked with transmembrane potential generation. The data obtained suggest that the electron translocation from 3-ketosteroid-delta'-dehydrogenase to O2 occurs via the respiratory chain. The enzyme donates reduced equivalents directly to the respiratory chain, presumably at the level of menaquinone.