Biomaterial Database

Synthesis and hydrolysis of ADP-arsenate by beef heart submitochondrial particles. 1983

S A Moore, and D M Moennich, and M J Gresser

The kinetic parameters for inorganic phosphate and inorganic arsenate as substrates for the synthesis of ATP and ADP-arsenate, respectively, by beef heart submitochondrial particles have been determined. The Vm and Km values for arsenate and phosphate, as well as the Km values for ADP in the two reactions, are the same within experimental error of the measurements. These data are consistent with covalent bond formation not being the rate-limiting step for either ATP or ADP-arsenate synthesis. The hydrolysis of ATP and of ADP-arsenate was studied under conditions of net synthesis of ATP or ADP-arsenate. The apparent first order rate constant for ATP hydrolysis increased with submitochondrial particle concentration, indicating that hydrolysis of ATP was catalyzed by the submitochondrial particle preparation. Nonenzymic hydrolysis of ATP was negligible compared to enzymic hydrolysis. The apparent first order rate constant for ADP-arsenate hydrolysis did not vary with submitochondrial particle concentration, indicating that ADP-arsenate hydrolysis was nonenzymic. Enzymic hydrolysis of ADP-arsenate was too slow, compared with its rapid nonenzymic hydrolysis, to be detected. The first order rate constant for ADP-arsenate hydrolysis at pH 7.5, 30 degrees C, was determined to be greater than 5 min-1 and was estimated to be 70 min-1. These data confirm previous suggestions that arsenate "uncouples" oxidative phosphorylation by a mechanism involving synthesis of ADP-arsenate, followed by its rapid nonenzymic hydrolysis.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D008929	Mitochondria, Heart	The mitochondria of the myocardium.	Heart Mitochondria,Myocardial Mitochondria,Mitochondrion, Heart,Heart Mitochondrion,Mitochondria, Myocardial
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D005954	Glucosephosphate Dehydrogenase		Glucose-6-Phosphate Dehydrogenase,Dehydrogenase, Glucose-6-Phosphate,Dehydrogenase, Glucosephosphate,Glucose 6 Phosphate Dehydrogenase
D006593	Hexokinase	An enzyme that catalyzes the conversion of ATP and a D-hexose to ADP and a D-hexose 6-phosphate. D-Glucose, D-mannose, D-fructose, sorbitol, and D-glucosamine can act as acceptors; ITP and dATP can act as donors. The liver isoenzyme has sometimes been called glucokinase. (From Enzyme Nomenclature, 1992) EC 2.7.1.1.	Hexokinase A,Hexokinase D,Hexokinase II
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2