Isolation of troponin-like complex from bovine brain cortex.

A troponin-like complex has been isolated from bovine brain cortex. This tropinin-like complex, with brain tropomyosin, confers Ca2+ sensitivity to the actin-activated myosin adenosinetriphosphatase (ATP phosphohydrolase, EC 3.6.1.3). That is, the Mg2+-stimulated ATPase activity generated by the interaction of purified muscle actin with muscle myosin is inhibited in the absence of Ca2+ but not in the presence of Ca2+ as a result of the addition of both brain tropomyosin and troponin-like complex. The troponin-like complex contains three components, one of which is similar in molecular weight to the troponin-T of skeletal actomyosin.