Biomaterial Database

Nicotinamide adenine dinucleotide binding and promotion of enzyme activity: model based on affinity labeling of 3 alpha, 20 beta-hydroxysteroid dehydrogenase with a nucleoside. 1981

F Sweet, and B R Samant

5'-[p-(Fluorosulfonyl)benzoyl]adenosine (FSA) was used to affinity-label the NADH binding region of 3 alpha, 20 beta-hydroxysteroid dehydrogenase (3 alpha, 20 beta-HSD) to further test our hypothesis [Sweet, F., & Samant, B. R. (1980) Biochemistry 19, 978-986] that 3 alpha and 20 beta activities occur at the same active site. Incubation of 3 alpha, 20 beta-HSD (0.45 microM) with FSA (125 microM) at pH 7.0 and 0 degrees C caused simultaneous loss of 3 alpha and 20 beta activities by a first-order kinetic process, with t1/2 = 300 min for both activities. Dinucleotides and adenosine mononucleotides which acted as competitive inhibitors protected 3 alpha, 20 beta-HSD against inactivation by FSA in a concentration-dependent manner, in the order reduced nicotinamide dinucleotide phosphate greater than oxidized nicotinamide dinucleotide phosphate greater than adenosine diphosphate-ribose greater than adenosine diphosphate greater than adenosine monophosphate (AMP) greater than adenosine. Oxidized and reduced nicotinamide mononucleotides (NMH and NMNH) and steroid substrates did not protect 3 alpha, 20 beta-HSD against affinity labeling by FSA. Although NMN was not a competitive inhibitor of 3 alpha, 20 beta-HSD, NMN with AMP and also AMP with NMNH produced positive cooperativity for competitive inhibition of 3 alpha, 20 beta-HSD. The results from FSA affinity labeling of the cofactor region confirm that both 3 alpha and 20 beta activities share the same active site of 3 alpha, 20 beta-HSD and suggest a model of cofactor binding and promotion of enzyme activity. The adenosine 5'-phosphate component anchors the NAD or NADH to an adenosine domain in the cofactor binding region. The nicotinamide nucleotide component then carries out the hydrogen-transfer reaction at a neighboring domain near the steroid binding region.

UI	MeSH Term	Description	Entries
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.
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
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