Separation of active and inactive (nonphosphorylating) Ca(2+)-ATPase in sarcoplasmic reticulum subfractions from low-frequency-stimulated rabbit muscle.
Chronic low-frequency stimulation elicits in rabbit fast-twitch muscle a partial inactivation of the sarcoplasmic reticulum (SR) Ca(2+)-ATPase and Ca(2+)-uptake activities. Inactive Ca(2+)-ATPase was enriched in a light microsomal fraction by sucrose density gradient centrifugation after calcium oxalate loading in the presence of ATP. This fraction showed a reduced specific activity and phosphoprotein formation of the Ca(2+)-transport ATPase. These results suggest that the inactivation of the Ca(2+)-ATPase as induced by increased contractile activity, is confined to a specific SR vesicle population.
Matsushita
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Fakultät für Biologie, Universität Konstanz, Germany.
Dux
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Pette
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D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification* / Q000378:metabolism; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D004558:Electric Stimulation; D004789:Enzyme Activation; D008297:Male; D008861:Microsomes / Q000201:enzymology; D009132:Muscles / Q000201:enzymology* / Q000648:ultrastructure; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D014357:Trypsin / Q000378:metabolism
D010710:Phosphates; D014357:Trypsin; D000252:Calcium-Transporting ATPases; D002118:Calcium