title: Primary structure of bovine vitamin K-dependent protein S.
abstract: Protein S is a vitamin K-dependent plasma protein that functions as a cofactor to activated protein C in the inactivation of coagulation factors Va and VIIIa. The nucleotide sequence of a full-length cDNA clone, obtained from a bovine liver library, was determined and the amino acid sequence was deduced. In addition, 95% of the structure was determined by protein sequencing. Protein S consists of 634 amino acids in a single polypeptide chain and has one asparagine-linked carbohydrate side chain. The cDNA sequence showed that the protein has a leader sequence, 41 amino acid residues long. The amino-terminal part of the molecule containing gamma-carboxyglutamic acid is followed by a region, residues 42-75, with two peptide bonds that are very sensitive to cleavage by thrombin. Residues 76-244 have four cysteinerich repeat sequences, each about 40 residues long, that are homologous to the precursor of mouse epidermal growth factor. In contrast to the other vitamin K-dependent plasma proteins, the carboxyl-terminal part of protein S is not homologous to the serine proteases.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001779:Blood Coagulation Factors / Q000235:genetics; D002417:Cattle; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004220:Disulfides; D006023:Glycoproteins / Q000235:genetics; D011487:Protein Conformation; D017293:Protein S; D014812:Vitamin K
chemical_list: D001779:Blood Coagulation Factors; D004220:Disulfides; D006023:Glycoproteins; D017293:Protein S; D014812:Vitamin K; D004247:DNA