Human Genes for Factor IX and other Vitamin K Dependent Blood Proteins
Factor IX is a plasma glycoprotein with m.w. 57,000. It is a single chain precurser to a serine protease which participates in the middle phase of blood coagulation. It is activated by factor XIa (activated factor XI) as well as by a complex of factor VII-tissue factor to a two chain form serine protease, factor IXa. Factor IX is one of the half a dozen blood proteins which require vitamin K for their normal biosynthesis. These proteins include factor VII, factor IX, factor X, prothrombin, protein C, protein S and protein Z. The first four proteins are blood coagulation factors. Protein C functions as an efficient regulator of blood coagulation by inactivating factors Villa and Va in the presence of protein S. Protein S also has a possible regulatory role in the complement system by binding to C4b binding2 protein. The function for protein Z is not known at the present time. The first about ten glutamic acid residues which are located within the amino-terminal about 40 amino acid sequence of these proteins are converted to gamma carboxylglutamic acid residues (gla residues) in a reaction catalyzed by a membrane-bound carboxylase(s) in the presence of vitamin K as a cofactor3. These gla residues in the proteins serve as the sites to bind calcium ions which are required for the optimal activities for these proteins.
KeywordsGlutamic Acid Residue Abnormal Factor Active Human Factor
Unable to display preview. Download preview PDF.
- 11.D. Diuguid, M. J. Rabiet, H. A. Liebman, B. C. Furie, and B. Furie, Factor IX Cambridge: hemophilia B caused by an unprocessed leader sequence on the factor IX NFLL-terminus, Blood 66:(suppl. 1), 333a (1985).Google Scholar
- 13.R. A. Blanchard, K. L. K. Faye, J. M. Barnet, and W. B. Castle, Isolation and characterization of profactor X from the liver of a steer treated with sodium warfarin, Blood 66:(suppl. 1), 331a (1985).Google Scholar
- 16.S. J. F. Degen and E. W. Davie, The prothrombin gene and serine protease evolution, Ann. NY Acad. Sci, in press (1986).Google Scholar
- 18.D. L. Freedenberg, S.-H. Chen, K. Kurachi, and C. R. Scott, Factor IX gene: localization of the MSP I polymorphic site, Human Genetics 39:(suppl.), A10 (1986).Google Scholar
- 21.T. Kojima, M. Tanimoto, T. Kamiya, Y. Obata, T. Takahashi, R. Ohno, K. Kurachi, and H. Saito, Possible absence of common polymorphisms in coagulation factor IX gene in Japanese, Blood in press (1986).Google Scholar
- 22.E. T. Pam, S.-H. Chen, K. Kurachi, and C. R. Scott, Lack of RFLP markers within the factor IX gene in Asian populations, Human Genetics 39:(suppl.), A243 (1986).Google Scholar
- 30.S.-H. Chen, C. R. Scott, R. Edson, and K. Kurachi, An insertion within the factor IX gene of hemophilia B El Salvador, Human Genetics submitted, (1986).Google Scholar
- 35.K. H. Choo, K. Raphael, W. McAdam, and M. G. Peterson, Expression of active human blood clotting factor IX in transgenic mice, Human Genetics 39:(suppl. 3), A192 (1986).Google Scholar