Protein C
Protein C's anticoagulant role in the human body was first noted by Seegers "et al." in 1960, who gave protein C its original name, "autoprothrombin II-a". Protein C was first isolated by Johan Stenflo from bovine plasma in 1976, and Stenflo determined it to be a vitamin K-dependent protein. He named it protein "C" because it was the third protein ("peak C") that eluted from a DEAE-Sepharose ion-exchange chromotograph. Seegers was, at the time, searching for vitamin K-dependent coagulation factors undetected by clotting assays, which measure global clotting function. Soon after this, Seegers recognised Stenflo's discovery was identical with his own. Activated protein C was discovered later that year, and in 1977 it was first recognised that APC inactivates Factor Va. In 1980, Vehar and Davie discovered that APC also inactivates Factor VIIIa, and soon after, Protein S was recognised as a cofactor by Walker. In 1982, a family study by Griffin "et al". first associated protein C deficiency with symptoms of venous thrombosis. Homozygous protein C deficiency and the consequent serious health effects were described in 1984 by several scientists. cDNA cloning of protein C was first performed in 1984 by Beckmann "et al." which produced a map of the gene responsible for producing protein C in the liver. In 1987 a seminal experiment was performed (Taylor "et al.") whereby it was demonstrated that activated protein C prevented coagulopathy and death in baboons infused with lethal concentrations of "E. coli."