A spin label study of the action of cupric and mercuric ions on human red blood cells.

The influence of heavy metal ions on human red blood cells was studied. Electron spin resonance studies of human erythrocytes labelled either with methyl 5-doxylpalmitate or methyl 12-doxylsterate indicated that cupric and mercuric ions increase the rigidity of membrane lipid bilayers. Both metals also induce conformational changes of membrane proteins and modify cell internal peptides and proteins as indicated by a 4-maleimido-2,2,6,6-tetramethylpiperidine-1-oxyl label ESR study. Copper and mercury ions decreased internal viscosity of red blood cells.