Factor IX San Dimas. Substitution of glutamine for Arg-4 in the propeptide leads to incomplete gamma-carboxylation and altered phospholipid binding properties.

Article Details

Citation

Ware J, Diuguid DL, Liebman HA, Rabiet MJ, Kasper CK, Furie BC, Furie B, Stafford DW

Factor IX San Dimas. Substitution of glutamine for Arg-4 in the propeptide leads to incomplete gamma-carboxylation and altered phospholipid binding properties.

J Biol Chem. 1989 Jul 5;264(19):11401-6.

PubMed ID
2738071 [ View in PubMed
]
Abstract

DNA sequence analysis of the Factor IX gene from a hemophilia B patient (98% Factor IX antigen; less than 0.01 unit/ml clotting activity) has identified a point mutation in exon II. A guanine to adenine transition causes the substitution of a glutamine codon for an arginine codon at -4 in the propeptide of Factor IX. This variant, termed Factor IX San Dimas, circulates in the plasma as proFactor IX with a mutant 18-amino acid propeptide still attached. Like Factor IX Cambridge (Arg-1----Ser), Factor IX San Dimas is unable to express metal-induced epitopes recognized by conformation-specific polyclonal antibodies. Amino acid analysis of the alkaline hydrolysate indicates that purified Factor IX San Dimas contains a reduced number of gamma-carboxyglutamyl residues compared to Factor IX. However, this protein undergoes metal-induced quenching of the intrinsic fluorescence. In addition, Factor IX San Dimas is unable to interact with phospholipid vesicles. The absence of coagulant activity in Factor IX San Dimas can be attributed to impaired calcium-induced conformational changes and loss in the ability to bind phospholipid vesicles in the presence of calcium ions.

DrugBank Data that Cites this Article

Polypeptides
NameUniProt ID
Coagulation factor IXP00740Details