Biomaterial Database

Affinity labeling of 3 alpha, 20 beta-hydroxysteroid dehydrogenase with a nucleoside analog. 1980

F Sweet, and B R Samant

Incubation of 3 alpha, 20 beta-hydroxysteroid dehydrogenase (3 alpha, 20 beta-HSD; E.C.1.1.1.53) with the nucleoside 5'-p-fluorosulfonylbenzoyladenosine (FSA) caused a time-dependent and irreversible loss in enzyme activity. Both 3 alpha- and 20 beta-hydroxysteroid oxidoreductase activities decreased at equal rates by a first order kinetic process (in 0.05M phosphate buffer at pH 6.0 and 25 degrees C, t1/2 = 170 min). Incubation of 3 alpha, 20 beta-HSD was quenched by addition of 2-mercaptoethanol which instantaneously reacts with the fluorosulfonyl group of FSA. The cofactor NADH protected 3 alpha, 20 beta-HSD against inactivation by FSA, in a concentration-dependent manner. However, progesterone did not protect 3 alpha, 20 beta-HSD against inactivation by FSA. Evidently, FSA causes inactivation of the enzyme by irreversibly binding to the NADH-binding region at the active site of 3 alpha, 20 beta-HSD. Both 3 alpha- and 20 beta-hydroxysteroid oxidoreductase activities disappeared at equal rates under a variety of enzyme-inactivating conditions. These results suggest that both 3 alpha- and 20 beta-activities occur at the same active site of 3 alpha, 20 beta-HSD.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009243	NAD	A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)	Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D003349	Cortisone Reductase	An enzyme that catalyzes the interconversion of a ketone and hydroxy group at C-20 of cortisone and other 17,20,21-trihydroxy steroids. EC 1.1.1.53.	20-beta-Hydroxysteroid Dehydrogenase,3 alpha,20 beta Hydroxysteroid Dehydrogenase,20 beta Hydroxysteroid Dehydrogenase,Dehydrogenase, 20-beta-Hydroxysteroid,Reductase, Cortisone
D000241	Adenosine	A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.	Adenocard,Adenoscan
D000345	Affinity Labels	Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids.	Affinity Labeling Reagents,Labeling Reagents, Affinity,Labels, Affinity,Reagents, Affinity Labeling
D013302	Streptomyces	A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.
D015089	20-Hydroxysteroid Dehydrogenases	A group of enzymes that catalyze the reversible reduction-oxidation reaction of 20-hydroxysteroids, such as from a 20-ketosteroid to a 20-alpha-hydroxysteroid (EC 1.1.1.149) or to a 20-beta-hydroxysteroid (EC 1.1.1.53).	20 Hydroxysteroid Dehydrogenases,Dehydrogenases, 20 Hydroxysteroid,Dehydrogenases, 20-Hydroxysteroid,Hydroxysteroid Dehydrogenases, 20
D055598	Chemical Phenomena	The composition, structure, conformation, and properties of atoms and molecules, and their reaction and interaction processes.	Chemical Concepts,Chemical Processes,Physical Chemistry Concepts,Physical Chemistry Processes,Physicochemical Concepts,Physicochemical Phenomena,Physicochemical Processes,Chemical Phenomenon,Chemical Process,Physical Chemistry Phenomena,Physical Chemistry Process,Physicochemical Phenomenon,Physicochemical Process,Chemical Concept,Chemistry Process, Physical,Chemistry Processes, Physical,Concept, Chemical,Concept, Physical Chemistry,Concept, Physicochemical,Concepts, Chemical,Concepts, Physical Chemistry,Concepts, Physicochemical,Phenomena, Chemical,Phenomena, Physical Chemistry,Phenomena, Physicochemical,Phenomenon, Chemical,Phenomenon, Physicochemical,Physical Chemistry Concept,Physicochemical Concept,Process, Chemical,Process, Physical Chemistry,Process, Physicochemical,Processes, Chemical,Processes, Physical Chemistry,Processes, Physicochemical