The effect of lead on the red cell membrane.

Introduction Many theories have been postulated for the interaction of lead with cell membranes (Hoogeveen, 1970; Aub et al., 1926; Maxwell and Bischoff, 1929; Clarkson and Kench, 1958). However, the mode of interaction and the resultant changes in cell membrane structure have not been investigated in depth. Lead also causes inhibition of the Na+/K+ ATPase pump of the erythrocyte (Hasan et al., 1967a; Hasan, Vikko and Hernberg, 1967b; Hernberg, Vikko and Hasan, 1967; Secchi and Alessio, 1969). The enzyme is sparsely distributed over the cell membrane as judged by its ouabain binding characteristics (Gardner and Coulon, 1972). Although it is known that the membrane-bound enzyme is inhibited, it is not known exactly which step in the complex mechanism of enzymic reaction is affected. Clearly, two modes of studying the cell membrane are available, namely, the study of changes in gross membrane lipoprotein structure, and the study of microscopic changes in the cell membrane as judged by alteration of enzymic activity. The former study was carried out by selective iodination of exposed tyrosine residues (Phillips and Morrison, 1971) and the latter by studying the high energy intermediates formed for the Na+/K+ ATPase reaction.