title: Interaction of lactate dehydrogenase with skeletal muscle troponin.
abstract: Rabbit muscle troponin complex covalently bound to CNBr-activated Sepharose 4B was shown to interact with soluble lactate dehydrogenase with a stoichiometry of 2 mol lactate dehydrogenase/mol of troponin. The presence of Ca2+ influenced the strength of association (the KD values of 0.73 and 2.3 microM were determined in the presence of 200 microM EGTA or 100 microM Ca2+, respectively). In the absence of Ca2+, the affinity of lactate dehydrogenase to troponin was strongly pH-dependent, reaching a maximum in the region of pH 6.0-7.0. No change of catalytic activity was observed as a result of interaction between lactate dehydrogenase and troponin, the enzyme appeared capable of functioning in the bound form.
authors.affiliation: A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, School of Biology, Moscow State University, U.S.S.R.
authors.lastname: Yasykova MYu
authors.forename: N B
authors.initials: NB
authors.lastname: Gusev
authors.forename: V I
authors.initials: VI
authors.lastname: Muronetz
authors.forename: N K
authors.initials: NK
authors.lastname: Nagradova
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D014336:Troponin / Q000378:metabolism*
chemical_list: D014336:Troponin; D004533:Egtazic Acid; D007770:L-Lactate Dehydrogenase; D002118:Calcium