Blood clotting factor IX BM Nagoya. Substitution of arginine 180 by tryptophan and its activation by alpha-chymotrypsin and rat mast cell chymase.
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Suehiro K, Kawabata S, Miyata T, Takeya H, Takamatsu J, Ogata K, Kamiya T, Saito H, Niho Y, Iwanaga S
Blood clotting factor IX BM Nagoya. Substitution of arginine 180 by tryptophan and its activation by alpha-chymotrypsin and rat mast cell chymase.
J Biol Chem. 1989 Dec 15;264(35):21257-65.
- PubMed ID
- 2592373 [ View in PubMed]
- Abstract
Factor IX BM Nagoya (IX Nagoya) is a natural mutant of factor IX responsible for severe hemophilia B. A patient with this mutant is characterized by a markedly prolonged ox brain prothrombin time. IX Nagoya was purified from the patient's plasma by immunoaffinity chromatography with an anti-factor IX monoclonal antibody column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that treatment of IX Nagoya with factor XIa/Ca2+ resulted in cleavage only at the Arg145-Ala146 bond. Reversed-phase high performance liquid chromatography of a trypsin digest of IX Nagoya showed an aberrant peptide, which was further digested with proteinase Asp-N. Primary structure analysis of one of the Asp-N peptides revealed that Arg180 is replaced by Trp. An essentially complete (99%) amino acid sequence of IX Nagoya was obtained by sequencing fragments derived from a lysyl endopeptidase digest in which no other substitutions in the catalytic triad or substrate binding site were found. We also found that IX Nagoya is activated by alpha-chymotrypsin or rat mast cell chymase by monitoring the rate of factor X activation using a fluorogenic peptide substrate in the presence of factor VIII, phospholipids, and Ca2+. These results indicate that the substitution of Arg180 by Trp impairs the cleavage by factor XIa required for activation of this zymogen and that the substitution causes hemophilia BM.