title: Separation of membranes from acid-solubilized fish muscle proteins with the aid of calcium ions and organic acids.
abstract: Calcium chloride, and to a lesser extent MgCl2, aided in the separation of membranes by centrifugation from cod (Gadus morhua) muscle homogenates solubilized at pH 3 in the presence of citric acid or malic acid but not lactic acid. Adding citric acid and Ca2+ before solubilizing the cod muscle homogenates was needed for the effect. At 1 mM citric acid, 70-80% of the phospholipid and 25-30% of the protein were removed at 10 mM Ca2+. At 8 mM Ca2+, citric acid showed an optimal effect on phospholipid removal at 5 mM with 90% of the phospholipid and 35% of the protein removed. The treatment with citric acid and Ca2+ was also effective in separating the membrane from solubilized herring (Clupea harengus) muscle homogenate. Ca2+ and citric acid might exert their influence by disconnecting linkages between membranes and cytoskeletal proteins.
authors.affiliation: Department of Food Science, Massachusetts Agricultural Experiment Station, University of Massachusetts/Amherst, Marine Station, Gloucester, Massachusetts 01930, USA. yliang@ufl.edu
authors.forename: Yong
authors.initials: Y
authors.lastname: Liang
authors.forename: Herbert O
authors.initials: HO
authors.lastname: Hultin
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry*; D002498:Centrifugation; D019343:Citric Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005399:Fishes; D048389:Gadus morhua; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D008293:Malates / Q000494:pharmacology; D009124:Muscle Proteins / Q000302:isolation & purification*; D012964:Sodium / Q000494:pharmacology; D012995:Solubility
chemical_list: D008293:Malates; D009124:Muscle Proteins; D019343:Citric Acid; C030298:malic acid; D012964:Sodium; D008274:Magnesium; D002118:Calcium