Abstract
Conditions for the satisfactory hydrolysis of human blood-group substances and the quantitative determination of their amino acids were established. The amino acid composition of more than 20 individual blood-group-specific mucopolysaccharides were closely similar, irrespective of the serological specificity within the ABO and Lewis blood-group systems. Possible functions for the amino acid-containing moiety of the muco-polysaccharide macromolecules are discussed.