The Ca2+-transport ATPases in smooth muscle.
A calmodulin stimulated Ca2+-transport ATPase which has many of the characteristics of the erythrocyte type Ca2+-transport ATPase has been purified from smooth muscle. In particular, the effect of calmodulin on these transport enzymes is mimicked by partial proteolysis and antibodies against erythrocyte Ca2+-transport ATPase also bind to the smooth muscle (Ca2+ + Mg2+)ATPase. A correlation between the distribution of the calmodulin stimulated (Ca2+ + Mg2+)ATPase and (Na+ + K+)ATPase activities in smooth muscle membranes separated by density gradient centrifugation suggests a plasmalemmal distribution of this (Ca2+ + Mg2+)ATPase. A phosphoprotein intermediate in smooth muscle which strongly resembles the corresponding phosphoprotein in sarcoplasmic reticulum of skeletal muscle may indicate the presence in smooth muscle of a similar type of Ca2+-transport ATPase.
Wuytack
F
F
Raeymaekers
L
L
Casteels
R
R
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000097:blood / Q000302:isolation & purification* / Q000378:metabolism; D002147:Calmodulin / Q000502:physiology; D002462:Cell Membrane / Q000201:enzymology; D004789:Enzyme Activation; D004910:Erythrocyte Membrane / Q000201:enzymology; D008861:Microsomes / Q000201:enzymology; D009130:Muscle, Smooth / Q000201:enzymology*; D009131:Muscle, Smooth, Vascular / Q000201:enzymology; D013552:Swine
D002147:Calmodulin; D000252:Calcium-Transporting ATPases; D002118:Calcium