PRE-STEADY STATE KINETICS OF E∼P FORMATION AND DECOMPOSITION BY Ca2+, Mg2+-ATPase IN BOVINE AORTA MICROSOMES

Publisher Summary It has been observed that vascular smooth muscle contains intracellular organelles, including sarcoplasmic reticulum(SR), which could regulate the cytosolic Ca 2+ concentration that activates the contractile apparatus. Microsomal fractions isolated from the vascular smooth muscle have been shown to take up Ca 2+ ions coupled to ATP hydrolysis; thus, these fractions have been suggested to be the counterparts of SR found in both skeletal and cardiac muscles. The chapter discusses a study to characterize the rates of the E∼P formation and decomposition using the rapid acid quench technique and to demonstrate presteady state profiles of phosphorylation identical to those found in skeletal and cardiac SR.