title: Comparative kinetic studies of Mn2+-activated and fructose-1,6-P-modified Mg2+-activated pyruvate kinase from Concholepas concholepas.
abstract: Initial velocity and product inhibition studies of Mn2+-activated and FDP-modified Mg2+-activated pyruvate kinase from Concholepas concholepas, were performed. Evidence is presented to show that the Mn2+-enzyme catalyzes an ordered sequential mechanism, with ADP being the first substrate and pyruvate the last product. The results presented are consistent with a random combination of reactants with the FDP-modified Mg2+-activated enzyme and the formation of the dead-end complexes enzyme ADP-ATP and enzyme-PEP-ATP.
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000494:pharmacology*; D006598:Hexosediphosphates / Q000494:pharmacology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008974:Mollusca; D009132:Muscles / Q000201:enzymology*; D011770:Pyruvate Kinase / Q000378:metabolism*
chemical_list: D005635:Fructosediphosphates; D006598:Hexosediphosphates; D011770:Pyruvate Kinase; D008274:Magnesium; C029063:fructose-1,6-diphosphate