title: Thermal instability of red blood cell membrane bilayers: temperature dependence of hemolysis.
abstract: Rates of human red blood cell hemolysis were measured as a function of temperature. Three distinct temperature intervals for hemolysis were noted: a) At temperatures equal to or less than 37 degrees C no hemolysis was observed for the duration of the incubation (30 hr). b) For temperatures exceeding 45 degrees C hemolysis rates are rapid and are accompanied by gross changes in cellular morphology. The activation energy for hemolysis is 80 kcal/mole; this value is characteristic of protein denaturation and enzyme inactivation suggesting that these processes contribute to hemolysis at these high temperatures. c) Between 38 and 45 degrees C the energy of activation is 29 kcal/mole, indicating that a fundamentally different process than protein inactivation is responsible for hemolysis at these relatively low temperatures. A mechanism based on the concept of the critical bilayer assembly temperature of cell membranes (N.L. Gershfeld, Biophys. J. 50:457-461, 1986) accounts for hemolysis at these relatively mild temperatures: The unilamellar state of the membrane is stable at 37 degrees C, but is transformed to a multibilayer when the temperature is raised; hemolysis results because formation of the multibilayer requires exposing lipid-free areas of the erythrocyte surface. An analysis of the activation energy for hemolysis is presented that is consistent with the proposed unilamellar-multibilayer transformation.
authors: Laboratory of Physical Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, Maryland 20892.
authors: N L
authors: NL
authors: Gershfeld
authors: M
authors: M
authors: Murayama
mesh_terms: D004910:Erythrocyte Membrane / Q000502:physiology*; D006461:Hemolysis; D006801:Humans; D007700:Kinetics; D008051:Lipid Bilayers; D008563:Membrane Lipids / Q000097:blood*; D010743:Phospholipids / Q000097:blood*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers; D008563:Membrane Lipids; D010743:Phospholipids