Interaction of lactate dehydrogenase with skeletal muscle troponin.
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.
Yasykova MYu
A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, School of Biology, Moscow State University, U.S.S.R.
Gusev
N B
NB
Muronetz
V I
VI
Nagradova
N K
NK
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*
D014336:Troponin; D004533:Egtazic Acid; D007770:L-Lactate Dehydrogenase; D002118:Calcium