title: Some kinetic singularities of Mg2+-dependent Mn-ATPase in rat brain synaptic membranes.
abstract: Mn(2+) stimulated change of Mg-ATPase activity has been found in the synaptic fraction of rat brain that was named Mn-ATPase. Investigation of the molecular mechanism has shown that Mn-ATPase is a multi-sited enzyme system whose minimum functional unit is a dimer. Its substrate is the MgATP complex. The number of sites for Mn(2+) as for essential activators and that of full-effect inhibitors are equal, n = m = 1. Studying regulation of the Mn-ATPase system by Mg(2+) has shown that Mg(2+) represents a double-sided effect modifier, namely, it activates the enzyme system at low concentration but inhibits at high concentration. Supposedly, binding-release of MgATP and Mg(2+) from the enzyme would be performed by a randomized mechanism. When analyzing experiments by using the kinetic method of complex curves, a "minimal model" for Mn-ATPase has been created.
authors.affiliation: Department of Membranology, Life Science Research Center, 14, Gotua Str, 0160, Tbilisi, Georgia. Kvitsinadze-nino@rambler.ru
authors.forename: Nino
authors.initials: N
authors.lastname: Kvitsinadze
authors.forename: Gvantsa
authors.initials: G
authors.lastname: Chkadua
authors.forename: Lia
authors.initials: L
authors.lastname: Shioshvili
authors.forename: Zurab
authors.initials: Z
authors.lastname: Kometiani
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000465:Algorithms; D000818:Animals; D001921:Brain / Q000201:enzymology*; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008954:Models, Biological; D051381:Rats; D013570:Synaptic Membranes / Q000201:enzymology*
chemical_list: D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; C032304:manganese ATPase