[Effect of cAMP-dependent phosphorylation on the activity of Mg2+,Ca2+-ATP-ase and Ca2+ transport in the sarcoplasmic reticulum of the white skeletal muscles of the rabbit].
It is shown that endogenic phosphorylation of sarcoplasmatic reticulum membranes in white skeletal muscles of rabbit stimulates Mg2+, Ca2+-ATPase activity and Ca2+ accumulation. When the level of endogenic phosphorylation is high, exogenic cAMP and protein kinase do not affect Mg2+, Ca2+-ATPase activity, when the level is low, they produce a 1.5-2-fold increase in the activity. The inhibitor of cAMP-dependent protein kinase practically completely eliminates the effect of endogenic phosphorylation on Ca2+ accumulation and Mg2+, Ca2+-ATPase activity. Under endogenic phosphorylation the Ca2+ binding constant becomes 1.8 times as low in sites of high affinity for this ion, and 4 times as low--in sites of low affinity.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D000242:Cyclic AMP / Q000502:physiology*; D066298:In Vitro Techniques; D009124:Muscle Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*
D009124:Muscle Proteins; D000242:Cyclic AMP; D011494:Protein Kinases; D017301:Ca(2+) Mg(2+)-ATPase; D000262:Adenylyl Cyclases; D000252:Calcium-Transporting ATPases; D002118:Calcium
Vliianie cAMP-zavisimogo fosforilirovaniia na aktivnost' Mg2+,Ca2+-ATP-azy i transport Ca2+ v sarkoplazmaticheskom retikulume belykh skeletnykh myshts krolika.