Affinity of the Ca2+ Binding Sites

There are two settings to evaluate the apparent affinity of the regulatory Ca2+ binding sites of thin filament:

1. Ca2+ dependent sliding speed of unloaded thin filaments in vitro;

2. Ca2+ activation of the thin filament-myosin S1 ATPase rate.

Heller, M.J., et al., Cardiomyopathic tropomyosin mutations that increase thin filament Ca2+ sensitivity and tropomyosin N-domain flexibility. J Biol Chem, 2003. 278(43): p. 41742-8