THE EFFECTS OF MITOMYCIN-C AND TEMPERATURE ON DYNAMICAL PROPERTIES OFHUMAN ERYTHROCYTE-MEMBRANE

Alterations produced by mitomycin-C (hereafter MC) and temperature cha nges in human erythrocyte membrane molecular dynamics were studied, in vitro, by spin-labeling ESR technique. Erythrocyte cells were spin-la beled with 5- and 16-doxyl-stearic acids, 5- and 16-DSA, respectively, and membrane fluidity was quantified by measuring the changes in the order parameter (S), correlation time (tau), phase transition temperat ure and activation energies. Erythrocyte cells were first labeled with 5-DSA and 16-DSA at 37 degrees C for 10 min, then they were treated w ith MC of three different concentrations (2.5; 5 and 10 mu M) for vari ous time (0-300 min) at the same temperature. Experimental results ind icate that treatment time and applied MC concentrations do not produce any significant reproducible changes in the spectral parameters. Howe ver, change in temperature was observed to alter significantly S and t au parameters that show biphasic character in the temperature range of 5-50 degrees C, Activation energy values of hydrocarbon chains above and below transition temperatures for unheated and MC-treated erythroc yte cells were also determined, and the effect of MC on these energy v alues were discussed. (C) 1997 Elsevier Science B.V.