title: [Two forms of Ca2+-dependent ATPase from sarcoplasmic reticulum].
abstract: Two highly purified sarcoplasmic reticulum membrane fractiones differing in their sensitivities to the uncoupling action of caffeine were isolated from white skeletal muscles of the rabbit. The main protein component of both fractions is a catalytical polypeptide of Ca2+-dependent ATPase. Treatment of the caffeine-sensitive reticular fraction by trypsin or DTNB completely removes the effect of caffeine. It was found that similar effects on the caffeine-sensitive reticular fraction are exerted by bemegride, camphor, ethymizole and cordiamine. Isolation of Ca2+-dependent ATPase from both reticular fractions and reconstruction of Ca2+-transporting vesicles were carried out. Ca2+ transport by the vesicles enriched by ATPase from the caffeine-sensitive reticular fraction is uncoupled under the effect of caffeine; however, caffeine has no effect on the vesicles enriched by caffeine-insensitive reticular ATPase. The molecular weight of caffeine-sensitive and caffeine-insensitive ATPases determined in the presence of sedium dodecyl sulfate are found to be identical. Electrophoresis in the presence of digitonin revealed different electrophoretic behaviour of the two forms of ATPase.
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification / Q000378:metabolism*; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
chemical_list: D007527:Isoenzymes; D002110:Caffeine; D004228:Dithionitrobenzoic Acid; D000252:Calcium-Transporting ATPases
vernacular_title: Dve formy Ca2+-zavisimoi ATPazy sarkoplazmaticheskogo retikuluma.