Chemical structure and properties of duck and goose fibrinogen

Duck and goose fibrinogen were isolated from fresh pooled plasma by three different methods. To minimize proteolytic activity, epsilon-aminocaproic acid and trasylol were used throughout the preparation procedures. Amino acid composition of fibrinogens and carbohydrate content (hexose, hexosamine, sialic acid) as well as phosphorus were analysed. Intact preparations showed single band on SDS-polyacrylamide gel electrophoresis. After reduction and modification of the thiol groups, the material could be separated by SDS-polyacrylamide gel electrophoresis into four bands corresponding to the gamma, partially degraded A alpha, B beta and intact A alpha chain. Intact polypeptide subunits were separated by ion-exchange chromatography or preparative SDS-polyacrylamide gel electrophoresis and their amino acid compositions were determined. Evidences supporting the view that bird fibrinogen is very sensitive to proteolytic degradation and that a partial degradation of the A alpha chain takes place even when inhibitors are used in all steps of the purification procedures are presented.