ESR-SPECTRUM STUDIES OF THE INFLUENCE OF FLUORIDE ON THE HUMAN ERYTHROCYTE-MEMBRANE PROTEIN SH BINDING-SITE PROPERTY

Healthy human erythrocyte membrane was labeled with the various chain lengths of maleimide nitroxide I, II, III, IV, and V, and their ESR sp ectra showed that sodium fluoride (NaF) decreases W/S (weakly immobili zed component/strongly immobilized component) ratio. Further experimen ts indicated that the reduction of W/S ratio due to fluoride is depend ent upon the following three factors: 1) Dose. W/S ratio is decreased with increasing dose of fluoride. 2) Time. With increasing exposure, t he tune required to reach the maximal ratio is shortened. 3) Temperatu re. Between 0-50-degrees-C, the point of phase transition is altered f rom 28.5-degrees-C in the control to 25.0-degrees-C. However, fluoride did not induce a change of the basic ESR spectra of the membrane prot ein SH when labeled with maleimide. An occurrence of the Q peak is dis cussed.