A lecithinase-lipase-negative Clostridium sp. 25.11.c., not fitting in any of the species of Clostridia described so far as judged by morphological, physiological, and biochemical data, was shown to contain NADP-dependent 3 beta-, 7 alpha- and 7 beta-hydroxysteroid dehydrogenases. The three hydroxysteroid dehydrogenases could be demonstrated in the supernatant and in the membrane fraction after solubilization with Triton X-100, suggesting enzymes which were originally membrane bound. The 3 beta-hydroxysteroid dehydrogenase was synthesized constitutively, and the specific enzyme activity was significantly reduced by growth medium supplementation with 3-keto bile acids and trisubstituted bile acids. A pH optimum of 7.5 and a molecular weight of approx. 104,000 were estimated by molecular sieve chromatography. The enzyme reduced the 3-keto group of bile acids; an oxidation of a 3 beta-hydroxyl function could not be demonstrated. The lowest Km values were found for disubstituted bile acids, trisubstituted and conjugated bile acids having higher Km values. 7 alpha-Hydroxysteroid dehydrogenase, but not 7 beta-hydroxysteroid dehydrogenase, was already present in uninduced cells. The specific activities, however, were greatly enhanced when cells were grown in the presence of chenodeoxycholic acid or 3 alpha-hydroxy-7-keto-5 beta-cholanoic acid. Ursodeoxycholic acid with its 7 beta-hydroxyl group was ineffective as an inducer. Molecular weights of approx. 82,000 and 115,000 were found for the 7 alpha-hydroxysteroid dehydrogenase and the 7 beta-hydroxysteroid dehydrogenase, respectively. In contrast to the in vivo situation, the reaction could only be demonstrated in the reductive direction in vitro. Here, the pH optimum for the overall reaction was 8.5-8.7. 3 beta-, 7 alpha- and 7 beta-hydroxysteroid dehydrogenase activities were readily demonstrated for at least 48 h when preparations were stored at 4 degrees C, but were found to be heat-sensitive.

Download full-text PDF

Source
http://dx.doi.org/10.1016/0005-2760(89)90061-1DOI Listing

Publication Analysis

Top Keywords

beta-hydroxysteroid dehydrogenase
20
bile acids
20
beta- alpha-
12
alpha- beta-hydroxysteroid
12
nadp-dependent beta-
8
dehydrogenase activities
8
lecithinase-lipase-negative clostridium
8
acids trisubstituted
8
alpha-hydroxysteroid dehydrogenase
8
dehydrogenase beta-hydroxysteroid
8

Similar Publications

Androgens are pleiotropic and play pivotal roles in the formation and variation of sexual phenotypes. We show that differences in circulating androgens between the three male mating morphs in ruff sandpipers are linked to 17-beta hydroxysteroid dehydrogenase 2 (HSD17B2), encoded by a gene within the supergene that determines the morphs. Low-testosterone males had higher expression in blood than high-testosterone males, as well as in brain areas related to social behaviors and testosterone production.

View Article and Find Full Text PDF

Obesity due to excessive body fat accumulation remains a global problem. Patients with obesity have high cortisol levels, and its dysregulation is caused by increased 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) levels. The effects and mechanism of J2H-1702, an 11β-HSD1 inhibitor, on nonalcoholic steatohepatitis (NASH) were explored.

View Article and Find Full Text PDF

Intrauterine growth restriction (IUGR) is a risk factor for postnatal cardiovascular, metabolic, and psychiatric disorders. In most IUGR models, placental dysfunction that causes reduced 11β-hydroxysteroid dehydrogenase 2 (11βHSD2) activity, which degrades glucocorticoids (GCs) in the placenta, resulting in fetal GC overexposure. This overexposure to GCs continues to affect not only intrauterine fetal development itself, but also the metabolic status and neural activity in adulthood through epigenetic changes such as microRNA change, histone modification, and DNA methylation.

View Article and Find Full Text PDF

Testosterone holds significant medical and economic importance, with the global market for testosterone replacement therapies valued at approximately USD 1.9 billion in 2023. This hormone is essential for the development and maintenance of male sexual characteristics as well as bone and muscle health.

View Article and Find Full Text PDF

This case report describes an adult man in his 50s with a history of type 2 diabetes and previously well-controlled hypertension, who presented with uncontrolled hypertension, muscle weakness and fatigue. Biochemical testing revealed hypokalaemia. There was no evidence of renal/renovascular disease.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!