A comparison of human prothrombin, factor IX (Christmas factor), factor X (Stuart factor), and protein S

Abstract

Human prothrombin, factor IX, and factor X have been idolated in high yield and characterized as the their amino-terminal sequence, molecular weight, amino acid composition, and migration in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An additional human plasma protein, called protein S, has also been purified and its properties have been compared with those of prothrombin, factor IX, and factor X. Prothrombin (mol wt 72 000), factor IX (mol wt 57 000), and protein S (mol wt 69 000) are single-chain glycoproteins, while factor X (mol wt 59 000) is a glycoprotein composed of two polypeptide chains held together by a disulfide bond(s). The amino-terminal sequence of the light chain of human factor X is homologous with prothrombin, factor IX, and protein S. The heavy chain of human factor X is slightly larger than the heavy chain of bovine factor X and differs from bovine factor X in its amino-terminal sequence.

Production of a self-activating CBM-factor X fusion protein in a stable transformed Sf9 insect cell line using high cell density perfusion culture

“…It is a complex glycoprotein with >50% of the carbohydrates on the activation peptide, and is also glycosylated at the C-terminus of the heavy chain (Assouline et al 1993;Inoue and Morita 1993;Di Scipio et al 1977;Cook et al 2000). The mature plasma form of factor X is a disulfide-linked two-chain molecule consisting of a light chain and a heavy chain, formed after intracellular proteolytic cleavage of the precursor (Leytus et al 1984).…”

Isolation and N‐terminal amino acid sequence of protein Z, A γ‐carboxyglutamic acid containing protein from bovine plasma

“…Two other proteins, protein C [2] and protein S [3,4], also containing Gla residues have been isolated from blood plasma after adsorption to barium salts. An additional Glacontaining protein, protein Z, isolated from bovine plasma was initially described as a singlechain variant of factor X [5,6].…”

Defining the Factor Xa-binding Site on Factor Va by Site-directed Glycosylation

“…It is composed of a Gla domain, two epidermal growth factor-like domains, an activation peptide, and a serine-protease domain. During blood coagulation, FX is activated by either the extrinsic pathway Factor VIIa⅐tissue factor complex or the intrinsic pathway tenase complex that comprises the phospholipidbound Factor IXa (FIXa) and activated FVIII (FVIIIa) (14). FVIIIa is a cofactor to FIXa in the activation of FX, a reaction that in many respects is very similar to the prothrombin activation (2).…”