Occurrence of degradation products of chicken transferrin in murine circulating blood.

ABSTRACT

To determine the true survival of an exogenous substance in the circulation, it is requisite to assess that of the intact molecules. We studied the survival of chicken transferrin (Tf) in murine circulating blood after i.v. injection. With the aid of polyacrylamide-gel isoelectric focusing, direct immunofixation and densitometry, degradation products of chicken Tfs were found, and the disappearance rate of intact molecules was rather higher than that obtained by the single radial immunodiffusion method. These results strongly suggest that the degradation products must be taken into consideration in studies on the clearance of proteinous substances.