Platelet fibrinogen. Identity and initial observations on the mode of its degradation by plasmin

Plasma and Platelet Fibrinogen Differ in γ Chain Content

“…3) mobilities (10, 12). The absence of the y57,5 chain in platelet fibrinogen represents a small structural difference from plasma fibrinogen and is unlikely to explain the differences previously reported between the platelet and plasma proteins in hydrody namic properties (9, 10), or plasmic degradation (10,11). The observed difference could, however, contribute to differences in immunological reactivity between platelet and plasma fibrinogen or their y chains (13).…”

“…D oolittle and colleagues (8) found sufficient similarities between the platelet and plasma proteins in the amino acid composition of fibrinopeptides, subunit polypeptide chain composition, crosslinking with Factor XIIIa, and N-terminal amino acid residues after thrombin treatment to conclude that both were products of a single gene or genes. Other studies, however, have identified significant differences between platelet and plasma fibrinogen in thrombin clottability (7,9,10), hydrodynamic properties (9, 10), carbohydrate content (10), pattern of plasmic degradation (10,11), molecular weight (10,12), and immunologi cal reactivity (13). In addition, Castaldi and Caen (5) and James and co-workers (14) have shown a lack of exchange between plasma and intraplatelet fibrinogen pools using isotopically labelled protein.…”