title: Characterization of cyclic 3':5'-amp-dependent protein kinase in sarcoplasmic reticulum and cytosol of canine myocardium.
abstract: Canine cardiac sarcoplasmic reticulum vesicles contain intrinsic cAMP-dependent and Ca2+ -calmodulin-dependent protein kinase (EC 2.7.1.37) activities and a common substrate, phospholamban, for these enzymes. Cyclic AMP-dependent protein kinase associated with sarcoplasmic reticulum membranes was solubilized with Triton X-100. Solubilization of the sarcoplasmic reticulum protein kinase did not affect its dependency on cAMP or its substrate specificity. The solubilized cAMP-dependent protein kinase was purified by DEAE-cellulose chromatography and was characterized as a type II enzyme on the basis of its elution at high ionic strength. DEAE-purified cAMP-dependent protein kinase exhibited no Ca2+ -calmodulin-dependent protein kinase activity. Cytosol from canine cardiac muscle cells, chromatographed on DEAE-cellulose under conditions identical to those used with sarcoplasmic reticulum, exhibited the presence of both type I and type II cAMP-dependent protein kinase isozymes. The properties of the DEAE-cellulose purified type II protein kinases from sarcoplasmic reticulum and cytosol were similar. We conclude that cardiac sarcoplasmic reticulum contains primarily type II cAMP-dependent protein kinase and this is probably the enzyme which phosphorylates sarcoplasmic reticulum in vivo and regulates Ca2+ transport.
mesh_terms: D000345:Affinity Labels / Q000494:pharmacology; D000818:Animals; D001386:Azides; D002458:Cell Fractionation; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D004285:Dogs; D007700:Kinetics; D046911:Macromolecular Substances; D009206:Myocardium / Q000201:enzymology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification* / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000201:enzymology* / Q000648:ultrastructure; D013379:Substrate Specificity
chemical_list: D000345:Affinity Labels; D001386:Azides; D046911:Macromolecular Substances; C017042:8-azidoadenosine-3',5'-monophosphate; D000242:Cyclic AMP; D011494:Protein Kinases