Kinetics of the conformational change of troponin-C induced by magnesium-binding or removal.
The kinetics of the conformation change of troponin-C (TN-C) induced by magnesium-binding or removal were studied in the absence of calcium ion by measuring the fluorescence intensity change of BIPM bound to TN-C by stopped-flow spectrofluorometry. The kinetic process of the conformational change was biphasic. The rate constants of the two phases were determined as a function of free magnesium ion concentration ([Mg]) of the solution. The [Mg]-dependence of the rate constants was explained by a simple molecular kinetic mechanism: (formula: see text) The dissociation constant of magnesium bound to TN-C was also determined to be 1 x 10(-3) M in the kinetic study.
D000818:Animals; D007700:Kinetics; D008274:Magnesium; D009124:Muscle Proteins; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014336:Troponin
D009124:Muscle Proteins; D014336:Troponin; D008274:Magnesium