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Ca2+ and the contractile proteins.

S Ebashi
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Abstract

Troponin regulation can be divided into two categories, primary and secondary. While the former underlies the processes common to troponin-regulated muscles, the latter varies between different types of muscle. One example of secondary regulation is the Ca2+ dependent interaction of troponin T and troponin C, which tends to suppress the myosin-actin-ATP interaction at relatively high Ca2+ concentrations, say, 10(-4)M. This interaction is marked in fast skeletal muscle, but weak in cardiac muscle. Since the Ca2+ concentration in fast skeletal muscle can physiologically reach a high level, this interaction may be considered as a kind of self-defense mechanism to avoid excess contraction. Cardiac muscle, which carries out its contractile cycle at lower Ca2+ concentrations, does not require such a mechanism, but under pathological conditions where the Ca2+ concentration could reach a high level, the lack of this mechanism might be detrimental to the contractile system.

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Adenosine TriphosphatasesAnimalsCalciumIn Vitro TechniquesMuscle ContractionMuscle ProteinsMusclesMyocardiumTroponinTroponin CTroponin TComparative StudyJournal ArticleReview

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S Ebashi. 1984. Ca2+ and the contractile proteins.. https://doi.org/10.1016/s0022-2828(84)80701-4

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