Properties of the sarcolemmal calcium ion-stimulated adenosine triphosphatase of hamster skeletal muscle.
1. A sarcolemmal fraction was isolated from hamster hind-leg skeletal muscles by successive treatment with lithium bromide and potassium chloride. The membranous fraction was observed to contain a highly active Ca(2+)-stimulated ATPase (adenosine triphosphatase), a Mg(2+)-stimulated ATPase, and an Na(+)+K(+)-stimulated Mg(2+)-dependent ouabain-sensitive ATPase. 2. The Ca(2+)-stimulated ATPase activity was pH-dependent, the optimum being pH7.6. 3. Optimum activation of this enzyme was obtained with 3-4mm-Ca(2+) when 4mm-ATP was present as a substrate, and was not influenced by Na(+), K(+) or ouabain, whereas 2,4-dinitrophenol, sodium azide, oligomycin, sodium fluoride and ethanedioxybis(ethylamine)tetra-acetate were inhibitory. 4. The Ca(2+)-stimulated ATPase was markedly inhibited by thiol-blocking reagents, and cysteine was able to reverse this inhibition. 5. Various bivalent cations stimulated ATP hydrolysis by the sarcolemmal fraction in the following decreasing order of potency: Mg(2+), Ca(2+), Mn(2+), Co(2+), Sr(2+), Ba(2+), Zn(2+), Cu(2+).
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate; D000818:Animals; D001386:Azides; D002118:Calcium; D006224:Cricetinae; D003545:Cysteine; D004140:Dinitrophenols; D004492:Edetic Acid; D004789:Enzyme Activation; D005459:Fluorides; D006614:Hindlimb; D006863:Hydrogen-Ion Concentration; D008094:Lithium; D008274:Magnesium; D009132:Muscles / Q000201:enzymology; D009840:Oligomycins; D010042:Ouabain; D011188:Potassium; D011189:Potassium Chloride; D012508:Sarcolemma / Q000201:enzymology*; D012964:Sodium
D001386:Azides; D004140:Dinitrophenols; D009840:Oligomycins; D010042:Ouabain; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D008094:Lithium; D004492:Edetic Acid; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D003545:Cysteine; D005459:Fluorides; D011188:Potassium; D002118:Calcium