Regulatory Protein of Bovine Tracheal Smooth Muscle

Abstract

Myosin B exhibiting Ca²⁺ sensitivity in superprecipitation and Mg-ATPase [EC 3.6.1.3] activity was extracted from tracheal smooth muscle. Repeated washing with 2 mM KC1 and I mM NaHCO₃ resulted in the loss of these activities. However, on addition of native tropomyosin, the myosin B regained its original properties. Native tropomyosin is the regulatory system in this smooth muscle.