title: Impedance spectroscopy of human erythrocyte membrane: effect of frequency at the spectrin denaturation transition temperature.
abstract: Thermal analysis of suspension impedance was applied at various frequencies, f, to study the changes in erythrocyte membranes (EM) over the temperature interval 47-53 degrees C where spectrin denatures. At f<crossover frequency (cof1) a decrease in EM resistance at 49.5 degrees C (A peak) has been observed. At f>cof1, when the capacitive conductance of EM becomes dominant, a second peak appeared at 50.5 degrees C (anti-A peak). The amplitudes of A and anti-A peaks reversibly depended on the phosphorylation of EM proteins. In contrast to the A peak, the anti-A peak was totally eliminated by modifications of EM with reagents that reduce EM deformability, O(s)O(4) (0.4-1mM) and putrescine (cytosolic concentration 1.5-2.0mM).
authors.affiliation: Department of Physics, Biophysics, Roentgenology and Radiology, Medical Faculty, Thracian University, Armeyska Str. 11, Stara Zagora 6000, Bulgaria. Ivanov_it@gbg.bg
authors.forename: I T
authors.initials: IT
authors.lastname: Ivanov
mesh_terms: D002470:Cell Survival; D017097:Electric Impedance; D004560:Electricity; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D010766:Phosphorylation; D011489:Protein Denaturation; D012965:Sodium Chloride / Q000737:chemistry / Q000378:metabolism; D013049:Spectrin / Q000737:chemistry* / Q000378:metabolism*; D044366:Transition Temperature
chemical_list: D008565:Membrane Proteins; D013049:Spectrin; D012965:Sodium Chloride