Effect of Two C-Terminal Side Chymotryptic Troponin T Subfragments on the Ca2+ Sensitivity of Superprecipitation and ATPase Activities of Actomyosin1

Abstract

The troponin T₂ (m.w. 13,000) subfragment showed a Ca²⁺ sensitizing action on the superprecipitation and ATPase activities of actomyosin in the presence of tro-pomyosin, troponin I, and troponin C. On the other hand, troponin T₂β (m.w. 11,000), the properties of which were similar to those of troponin T2α except for the lower affinity for tropomyosin, did not show the Ca²⁺ sensitizing action.