title: Critical temperatures for the interaction of free fatty acids with the erythrocyte membrane.
abstract: Non-esterified long-chain fatty acids reduce the extent of hypotonic hemolysis at a certain low concentration range but cause hemolysis at higher concentrations. This biphasic behavior was investigated at different temperatures (0-37 degrees C) for lauric (12:0), myristic (14:0), palmitoleic (16:1), oleic (cis-18:1) and elaidic (trans-18:1) acids. The results are summarized as follows: (A) the fatty acids examined exhibit a high degree of specificity in their thermotropic behavior; (B) oleic acid protects against hypotonic hemolysis even at the highest concentrations, up to 15 degrees C, when it becomes hemolytic, but only in a limited concentration range; (C) elaidic acid does not affect the osmotic stability of erythrocytes up to 20 degrees C, when it starts protecting: above 30 degrees C, it becomes hemolytic at the highest concentrations; (D) palmitoleic acid is an excellent protecting agent at all temperatures in a certain concentration range, becoming hemolytic at higher concentrations; (E) lauric acid protects up to 30 degrees C and becomes hemolytic only above this temperature; (F) myristic acid exhibits an extremely unusual behavior at 30 and 37 degrees C by having alternating concentration ranges of protecting and hemolytic effects; (G) there is a common critical temperature for hemolysis at 30 degrees C for saturated and trans-unsaturated fatty acids; (H) the initial slope of Arrhenius plots of percent hemolysis at the concentration of maximum protection is negative for cis-unsaturated fatty acids and positive for saturated and trans-unsaturated fatty acids.
authors.affiliation: Institute of Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Csordas
authors.forename: M
authors.initials: M
authors.lastname: Rybczynska
mesh_terms: D004910:Erythrocyte Membrane / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D006801:Humans; D007850:Lauric Acids / Q000097:blood; D019814:Myristic Acid; D009227:Myristic Acids / Q000097:blood; D019301:Oleic Acid; D009829:Oleic Acids / Q000097:blood; D009996:Osmotic Fragility; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000097:blood; D013696:Temperature
chemical_list: D005230:Fatty Acids, Nonesterified; D007850:Lauric Acids; D009227:Myristic Acids; D009829:Oleic Acids; D010169:Palmitic Acids; D019814:Myristic Acid; C030358:lauric acid; D019301:Oleic Acid; D019308:Palmitic Acid; C011459:elaidic acid