title: A fluorescence quenching study of tryptophanyl residues of (Ca2+ + Mg2+)-ATPase from sarcoplasmic reticulum.
abstract: The tryptophan intrinsic fluorescence of the (Ca2+ + Mg2+)-ATPase from sarcoplasmic reticulum was quenched by acrylamide at different temperatures. Sharp increases in the quenching constants were found in samples of ATPase reconstituted with dimyristoyl-phosphatidylcholine and dipalmitoylphosphatidylcholine at temperatures slightly below the Tc transition temperature of the pure phospholipid. It is suggested that acrylamide may diffuse more easily through proteins surrounded by a fluid phospholipid matrix than if they are in a rigid matrix, due to different states of protein fluidity.
authors.forename: J C
authors.initials: JC
authors.lastname: Gómez-Fernández
authors.forename: M D
authors.initials: MD
authors.lastname: Baena
authors.forename: J A
authors.initials: JA
authors.lastname: Teruel
authors.forename: J
authors.initials: J
authors.lastname: Villalaín
authors.forename: C J
authors.initials: CJ
authors.lastname: Vidal
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004134:Dimyristoylphosphatidylcholine / Q000494:pharmacology; D007700:Kinetics; D009132:Muscles / Q000201:enzymology; D011663:Pulmonary Surfactants / Q000494:pharmacology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013816:Thermodynamics; D014364:Tryptophan / Q000032:analysis*
chemical_list: D011663:Pulmonary Surfactants; D014364:Tryptophan; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D004134:Dimyristoylphosphatidylcholine