Properties of membrane-bound and soluble guanylate cyclase of cardiac and skeletal muscle
Sulakhe, S.J.; Sulakhe, P.V.
Recent Advances in Studies on Cardiac Structure and Metabolism 11: 257-263
1976
ISSN/ISBN: 0363-5872 PMID: 22902 Document Number: 103041
Kinetic properties of guanylate cyclase present in the washed particles, plasma membranes, and the soluble cytoplasm of heart and skeletal muscle are described; properties of the enzyme solubilized by Triton X-100 treatment of the particles or membrane fractions are also reported. It is apparent from the data that the membrane-bound guanylate cyclase in the cell may be regulated by acetylcholine, may exist as a metallo-protein with bound Mn2+ (essential for activity), and that Mg2+ regulates, whereas Ca2+ and nucleotides (especially ATP) modulate, guanylate cyclase activity. The findings also suggest that guanylate cyclase, similar to adenylate cyclase and (Na+, K+)-ATPase, is mainly located in the plasma membranes of heart and skeletal muscle.