[Effect of calcium ions on the interaction of troponin C with rabbit skeletal muscle troponin I and troponin T immobilized on polyvinyl chloride].

Feoktistov IA, Krylatov AV, Zabeń≠vorota SI, Cherviakov EB, Larionov NP
Biokhimiia. 1989 54 (2): 265-72

PMID: 2742925

Using a new methodological approach based on the binding of 125I-labeled troponin C to troponins I and T immobilized on polyvinylchloride, the Ca2+-dependent interaction of troponin components was investigated. In the absence of Ca2+, two types of sites of troponin C--troponin T interaction were revealed (Kd = 3.6.10(-8) M and 5.10(-7) M). It was found that Ca2+ induced the formation of a troponin I--troponin C complex which was resistant to 5 M urea (Kd = 4.10(-8) M). In the absence of Ca2+, the binary troponin T--troponin C complex also revealed two types of interaction sites (Kd = 7.1.10(-8) M and 2.10(-7) M); however, in the presence of Ca2+ only high affinity sites whose number increased almost 2-fold were revealed. The events that may take place in the whole troponin complex during Ca2+ binding by troponin C are discussed.

MeSH Terms (15)

Animals Benzothiazoles Binding, Competitive Calcium Carbocyanines Fluorescent Dyes In Vitro Techniques Muscles Polyvinyl Chloride Rabbits Troponin Troponin C Troponin I Troponin T Urea

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