Heterogeneity of Bovine Fibrinogen and Fibrin

• Published in: The Journal of biological chemistry 1973-10, Vol.248 (19), p.6896-6903
• Main Authors: Mosher, D F, Blout, E R
• Format: Article
• Language: English
• Subjects: Animals; Cattle; Chromatography, DEAE-Cellulose; Chromatography, Ion Exchange; Dialysis; Electrophoresis, Polyacrylamide Gel; Female; Fibrin - analysis; Fibrinogen - analysis; Fibrinogen - isolation & purification; Humans; Molecular Weight; Neuraminic Acids - analysis; Oxidation-Reduction; Peptides - analysis; Phosphates - analysis; Sodium Dodecyl Sulfate; Spectrophotometry; Spectrophotometry, Ultraviolet
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)43434-0

We have attempted to relate the heterogeneity found when native bovine fibrinogen, which is known to have the subunit structure [Aα Bβ γ] 2 , was chromatographed on DEAE-Sephadex A-50, to electrophoretic differences among the constituent polypeptide chains and differences in the content of charged groups. Bovine fibrinogen, purified from the blood of individual animals, eluted from DEAE-Sephadex A-50 as three major peaks, each of which appeared heterogeneous. Two γ chains were distinguished by polyacrylamide gel electrophoresis of the reduced, S -carboxymethylated derivative of unchromatographed fibrinogen in 8 m urea at pH 8.6. Fibrin from the first major chromatographic peak contained only the more cationic γ chain. Fibrin from the second peak contained equal amounts of the two γ chains as judged by densitometry of stained gels. Fibrin from the third peak contained predominantly the more anionic γ chain. These findings indicate that separation into the three major peaks is due to the three possible combinations of two different γ chains in native fibrinogen. Since a Ferguson plot of the relative mobilities of the two γ chains versus gel concentration in 8 m urea at pH 9.5 yielded parallel lines, and since the two γ chains were not separated by polyacrylamide gel electrophoresis in 0.1% sodium dodecyl sulfate at pH 7.0, it is likely that the two γ chains differ in charge but not in size. Analyses of fractions within each of the major peaks suggest that heterogeneity within the peaks is due to differences in phosphate content, which varied from 0.6 to 3.8 moles of phosphate per mole of fibrinogen. These observations indicate that within an individual animal there are as many as 36 different fibrinogen molecules, differing either in the composition of γ chains or in the content of bound phosphate.