title: Different thermostabilities of sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPases from rabbit and trout muscles.
abstract: Trout and rabbit (Ca2+ + Mg2+)-ATPases from sarcoplasmic reticulum were compared for differences in thermal inactivation and susceptibility to trypsin digestion. The trout ATPase is more heat-sensitive than the rabbit ATPase and is stabilized by Ca2+, Na+, K+ and nucleotides. Solubilization of both ATPases shows that the two ATPases have different protein-intrinsic inactivation kinetics. When digested by trypsin, the two ATPases display different cleavage patterns. The present results indicate that the trout and rabbit ATPases have dissimilarities in protein structure that may explain the differences in thermal inactivation kinetics.
authors.affiliation: Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: F G
authors.initials: FG
authors.lastname: de Toledo
authors.forename: M C
authors.initials: MC
authors.lastname: Albuquerque
authors.forename: B H
authors.initials: BH
authors.lastname: Goulart
authors.forename: E N
authors.initials: EN
authors.lastname: Chini
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000502:physiology; D004795:Enzyme Stability / Q000187:drug effects / Q000502:physiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008024:Ligands; D008094:Lithium / Q000494:pharmacology; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism; D017830:Octoxynol / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology* / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology; D012995:Solubility; D013050:Spectrometry, Fluorescence; D014337:Trout; D014357:Trypsin / Q000378:metabolism
chemical_list: D008024:Ligands; D017830:Octoxynol; D008094:Lithium; D012964:Sodium; D014357:Trypsin; D017301:Ca(2+) Mg(2+)-ATPase; D011188:Potassium