title: Dinucleosidetriphosphatase from rat brain.
abstract: Rat brain P1,P3-bis(5'-adenosyl)-triphosphate adenylohydrolase (dinucleosidetriphosphatase, EC 3.6.1.29) was purified 1000-fold. The enzyme hydrolyzed diadenosine and diguanosine triphosphates (Km values 14 and 40 microM, and relative V 100 and 40, respectively) to the corresponding nucleoside di and monophosphates. Dixanthosine triphosphate was hydrolyzed at a residual rate. Diadenosine di and tetraphosphates, NAD+, and artificial phosphodiesterase substrates were not hydrolyzed. Bivalent cations [Mg(II), Mn(II) or Ca(II)] were required for activity, but Zn(II) was a competitive inhibitor (Ki = 5 microM). The optimum pH value was about 7.5. A molecular mass of 34 kdalton (gel filtration) and an isoelectric point of 5.5 (chromatofocusing) were found.
mesh_terms: D017766:Acid Anhydride Hydrolases; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002413:Cations, Divalent; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D002413:Cations, Divalent; D010744:Phosphoric Monoester Hydrolases; D000099170:Bis(5'-adenosyl)triphosphatase