[The role of nonspecific troponin in kinetics of intracellular calcium in cardiomyocytes].
According to literature data nonspecific troponin TnC2 binds calcium in cardiac myocytes slowly and does not influence calcium transient. Therefore TnC2 often was not taken into consideration in models of the intracellular calcium kinetics. The mathematical model of the intracellular Ca(2+)-binding system we developed includes TnC2 as a ligand. Rate constants accepted for the complexation of Ca2+ by intracellular ligands give good agreement of the theoretical data with observed physiological ones. We compared the results of numerical experiments on this model with similar results obtained on the other model where TnC2 had been ignored. Some essential differences were revealed. In the model without TnC2 the fraction of calcium binding to specific troponin TnC1 always is smaller than the fraction of Ca2+ bound to the other ligands together. In our model TnC1 fraction (it regulates the mechanical response of muscle) is bigger that means more effective Ca(2+)-binding during activation of contractile proteins. The results above show that within the frame of our model the constants taken for Ca(2+)-binding ligands are more substantiate.
Solov'eva
O E
OE
Markhasin
V S
VS
Katsnel'son
L B
LB
D002118:Calcium / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding; D014336:Troponin / Q000378:metabolism*
D008024:Ligands; D014336:Troponin; D002118:Calcium