Purification and properties of the phenprocoumon-induced decarboxyfactor x from bovine plasma: A comparison to normal factor x

By a procedure involving adsorption to barium sulfate, chromatography on DEAE-Sephadex and QAE[quaternary ammonium ethyl]-Sephadex and preparative polyacrylamide gel electrophoresis, decarboxyfactor X was purified from plasma of phenprocoumon-treated cows. No contaminants could be detected in the final preparation by polyacrylamide gel electrophoresis and zone-electrophoresis. The MW of decarboxyfactor X, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis is approximately 55,000, which is equal to that of factor X. The protein consists of 2 polypeptide chains with MW of 44,000 and 17,000. Decarboxyfactor X has antigenic determinants in common with normal factor X. The amino acid composition and amino-terminal amino acids of normal factor X and decarboxyfactor X are identical. Less than 1 residue of .gamma.-carboxyglutamate could be detected per mole of decarboxyfactor X. In the absence of Ca2+, normal factor X has a slightly higher electrophoretic mobility than decarboxyfactor X. In the presence of Ca2+ the mobility of factor X decreases considerably while the mobility of decarboxyfactor X remains unaltered.