Influence of polyethylene glycol on the structure of the erythrocyte membrane: an ESR study

Using a fatty acid spin label (I (10, 3)) it was found that the membrane fluidity of intact human erythrocytes is not influenced by polyethylene glycol (PEG) up to a concentration of 10 wt%. On the contrary a drastic effect of PEG on the spectrum of maleimide spin labeled membrane proteins of erythrocyte ghosts were detected. It is suggested that aggregation and/or conformational changes of membrane proteins were induced by PEG.