title: Cathepsin G, a regulator of human vitamin K, dependent clotting factors and inhibitors.
abstract: Cathepsin G was used in vitro to digest human factor VII and factor IX. Clotting assays indicated that the proteinase affected a rapid loss in coagulant activity while in the presence of calcium ions the activity was almost totally protected. SDS-polyacrylamide gel electrophoresis indicated the removal of a peptide from each zymogen, VII-L from factor VII and IX-L from factor IX. This lead to the formation of VII-H and IX-H respectively. N-terminal analysis of the VII-H and IX-H products and COOH-terminal analysis of the VII-L and IX-L products confirmed that cathepsin G had cleaved position Phe40:Trp41 in factor VII and factor IX. The cleavage site is the same as that when cathepsin G is reacted with factor II, factor X and protein C. The unique action of cathepsin G may be part of a regulatory system for controlling the coagulant activity of vitamin K dependent clotting in vivo.
authors.affiliation: Department of Medical Technology, Kuwait University.
authors.forename: P T
authors.initials: PT
authors.lastname: Turkington
mesh_terms: D000595:Amino Acid Sequence; D001777:Blood Coagulation / Q000187:drug effects; D056649:Cathepsin G; D002403:Cathepsins / Q000302:isolation & purification / Q000494:pharmacology*; D005164:Factor IX / Q000378:metabolism*; D005167:Factor VII / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000201:enzymology; D016415:Sequence Alignment; D012697:Serine Endopeptidases; D014812:Vitamin K / Q000378:metabolism*
chemical_list: D014812:Vitamin K; D005167:Factor VII; D005164:Factor IX; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G