Biomaterial Database

Characterization of a corticosteroid 21-dehydroxylase from the intestinal anaerobic bacterium, Eubacterium lentum. 1980

S D Feighner, and P B Hylemon

An oxygen-sensitive corticosteroid 21-dehydroxylase has been characterized in cell extracts of Eubacterium lentum. The enzyme was highly specific for corticosteroids containing and alpha-ketol structure and required FMNH2 or reduced benzyl viologen for activity. The enzyme used deoxycorticosterone, deoxycortisol, dehydrocorticosterone, and corticosterone as substrates. Substrate saturation kinetics using [3H]corticosterone yielded an apparent Km of 7.35 microM and a Vmax of 15.4 nmol (11 beta-[3H]hydroxyprogesterone) formed per hr x mg protein-1. 21-Dehydroxylase activity was inhibited by both water-soluble and lipophilic metal ion chelators. NADH: flavin oxidoreductase and 21-dehydroxylase activities were separated by anaerobic DEAE-cellulose and Sepharose 6B chromatography. 21-Dehydroxylase had a relative weight of 582,000 as determined by Sepharose 6B chromatography. There was a 7-fold increase in the rate of 21-dehydroxylation of [3H]deoxycorticosterone in whole cell suspensions of E. lentum sparged with H2 as compared to argon gas.

UI	MeSH Term	Description	Entries
D007422	Intestines	The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.	Intestine
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D005051	Eubacterium	A genus of gram-positive, rod-shaped bacteria found in cavities of man and animals, animal and plant products, infections of soft tissue, and soil. Some species may be pathogenic. No endospores are produced. The genus Eubacterium should not be confused with EUBACTERIA, one of the three domains of life.	Butyribacterium
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000693	Anaerobiosis	The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Anaerobic Metabolism,Anaerobic Metabolisms,Anaerobioses,Metabolism, Anaerobic,Metabolisms, Anaerobic
D013250	Steroid Hydroxylases	Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.	Steroid Hydroxylase,Steroid Monooxygenases,Hydroxylase, Steroid,Hydroxylases, Steroid,Monooxygenases, Steroid
D013255	Steroid 21-Hydroxylase	An adrenal microsomal cytochrome P450 enzyme that catalyzes the 21-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP21 gene, converts progesterones to precursors of adrenal steroid hormones (CORTICOSTERONE; HYDROCORTISONE). Defects in CYP21 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL).	Cytochrome P-450 CYP21,Steroid 21-Monooxygenase,21-Hydroxylase,Cytochrome P-450 21-Hydroxylase,Cytochrome P-450 c21,Cytochrome P-450(c-21),Cytochrome P450c21,Progesterone 21-Hydroxylase,Steroid-21-Hydroxylase,21 Hydroxylase,Cytochrome P 450 21 Hydroxylase,Cytochrome P 450 CYP21,Cytochrome P 450 c21,P-450 c21, Cytochrome,Progesterone 21 Hydroxylase,Steroid 21 Hydroxylase,Steroid 21 Monooxygenase
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities