Properties of the Ca-pumping ATPase of sarcoplasmic reticulum from vascular smooth muscle.
A microsomal fraction enriched in sarcoplasmic reticulum membranes has been isolated from bovine aorta smooth muscle. The properties of the Ca-pumping ATPase were compared to those of the enzymes of skeletal and cardiac sarcoplasmic reticulum. The kinetic (Km and turnover rate) and structural (tryptic digestion pattern) properties of the three ATPases were strikingly similar. The three enzymes, however, displayed (almost) no immunological cross-reactivity. Skeletal muscle sarcoplasmic reticulum and aorta microsomes did not contain phospholamban: their Ca-pumping activity was not regulated by either a cAMP-dependent or a calmodulin-dependent pathway.
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D003429:Cross Reactions; D000242:Cyclic AMP / Q000378:metabolism; D004285:Dogs; D007700:Kinetics; D008970:Molecular Weight; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D014357:Trypsin / Q000378:metabolism
D002147:Calmodulin; D000242:Cyclic AMP; D011494:Protein Kinases; D014357:Trypsin; D000252:Calcium-Transporting ATPases