The physicochemical and chemical properties of alpha 1-acid glycoproteins from mammalian and avian plasmas.

We have isolated from the plasma of man, rabbit, pig, rat and chicken alpha 1-acid glycoproteins that show a single band on polyacrylamide gel electrophoresis and a single arc in immunodiffusion. Amino acid and carbohydrate compositions are presented. The human protein is very similar to preparations described by earlier workers and, although significant differences in amino acid composition exist among them, the proteins from the other species are assumed to be analogous to it. Ultra centrifugal studies, despite showing single, fairly symmetrical peaks at high speed, produced evidence for the physical heterogeneity of each protein in agreement with some earlier reports. Although many models consisting of mixtures of components were tested, none was found that fitted adequately all observations on any one of the glycoproteins.