Species differences of clotting factors in ox, dog, horse, and man: proaccelerin and accelerin.

The research explores clotting factors in different species – ox, dog, horse and man – focusing specifically on proaccelerin and accelerin. It delves into their role in blood coagulation and identifies notable species differences.

Significance of Proaccelerin and Accelerin

• Proaccelerin and accelerin play pivotal roles in blood clotting or coagulation.
• Proaccelerin, which is also known as factor V, labile factor, or plasma Ac-globulin, significantly influences the rate at which thrombin is formed and the quantity of thrombin produced during coagulation.
• During coagulation, proaccelerin is converted by thrombin into accelerin (serum Ac-globulin) which is a more active product.
• This transition of proaccelerin into accelerin is fundamental to the mechanism of thrombin formation, essentially making proaccelerin critical in the pseudo-autocatalytic mechanism.

Species Differences in Coagulation

• Despite the wide use of proaccelerin and accelerin from different species in coagulation studies, not much attention has been given to the differences across species.
• The study indicates that species differences were previously inferred based on experiments involving prothrombin accelerator (identical to proaccelerin) using plasma from different species like rabbit, dog, guinea pig, and human.
• The resulting activities of plasma decreased in the order mentioned, aligning with the variant concentrations of proaccelerin in the plasma of each species.
• Historical data concerning species differences primarily involves quantitative estimations of proaccelerin concentration in different species, as noted in Quick’s and Seegers’ laboratories.

Qualitative Differences of Proaccelerin

• Established qualitative differences between species are rare, with one notable distinction mentioned in the study: proaccelerin derived from oxen (bovine) plasma is more stable than its human counterpart.
• This stability distinction was first noted by another researcher, Owren, in 1947.