Factor IX: Difference between revisions
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== Serine Protease Domain == | == Serine Protease Domain == | ||
{{STRUCTURE_1rfn| PDB=1rfn | | {{STRUCTURE_1rfn| PDB=1rfn | SIZE=300| SCENE= |right| CAPTION=human factor IX EGF2-catalytic domain complex with inhibitor, [[1rfn]] }} | ||
The serine protease domain of FIX is required for blood coagulation<ref>PMID:10467178</ref>. FIX circulates in plasma as a single-chain zymogen at a concentration of 2.5-5 mg/ml and a half life is approximately 24 hours. The zymogen is activated by either FVII–tissue-factor complex or Factor XIa (FXIa). During activation the peptide bonds between Arg145–Ala146 and Arg180–Val181 are cleaved releasing an 11 kDa activation peptide from the Factor IX. This cleavage allows the exposure of the serine protease site on the heavy chain which can then activate Factor X in the presence of Factor VIII, calcium and phospholipid surface. This enzyme belongs to the family of trypsin-like serine proteases.The mechanism of these serine proteases involves the catalytic triad, which is found in the enzymes active site and is composed of three amino acids. | The serine protease domain of FIX is required for blood coagulation<ref>PMID:10467178</ref>. FIX circulates in plasma as a single-chain zymogen at a concentration of 2.5-5 mg/ml and a half life is approximately 24 hours. The zymogen is activated by either FVII–tissue-factor complex or Factor XIa (FXIa). During activation the peptide bonds between Arg145–Ala146 and Arg180–Val181 are cleaved releasing an 11 kDa activation peptide from the Factor IX. This cleavage allows the exposure of the serine protease site on the heavy chain which can then activate Factor X in the presence of Factor VIII, calcium and phospholipid surface. This enzyme belongs to the family of trypsin-like serine proteases.The mechanism of these serine proteases involves the catalytic triad, which is found in the enzymes active site and is composed of three amino acids. | ||