Abstract
The electrokinetic procedures used for investigation of the nature and distribution of cellular surface charge groups are outlined. The application of ion binding studies, the action of enzymes, and the effects of specific functional group reagents are illustrated by discussion of the results obtained for erythrocytes and thrombocytes. The human erythrocyte has been shown to be a macropolyanion possessing about 107 charged groups per cell of which more than 60% are the carboxyl group of N‐acetylneuraminic acids; some of the remaining groups at least are the α‐carboxyl groups of protein‐bound amino acids. The electrokinetic constitution of the human blood platelet is more complex and includes sialic acid carboxyl groups and phosphate groups and at least one other species of unidentified anionogenic groups as well as amino groups. Lastly the effects of neutral and charged polymer adsorption on the electrokinetic properties of blood cells are briefly considered.