Factor IX: Difference between revisions
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[[Image:Research_02_big4.JPG|frame|right|http://www.molecular-haemostasis.de/grfx/pix/]] | [[Image:Research_02_big4.JPG|frame|right|http://www.molecular-haemostasis.de/grfx/pix/]] | ||
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The post-translational modification of the glutamic acid residues of the FIX polypeptide is carried out by vitamin K-dependent ''γ''-glutamyl carboxylase <ref>PMID:902786</ref>. Vitamin K-dependent carboxylase is a membrane associated protein in the endoplasmic reticulum. It converts a multiple of glutamic acid residues which are located within 40 residues of a propeptide-containing sequence into ''γ''-carboxyglutamate <ref>PMID:8530480</ref>. | The post-translational modification of the glutamic acid residues of the FIX polypeptide is carried out by vitamin K-dependent ''γ''-glutamyl carboxylase <ref>PMID:902786</ref>. Vitamin K-dependent carboxylase is a membrane associated protein in the endoplasmic reticulum. It converts a multiple of glutamic acid residues which are located within 40 residues of a propeptide-containing sequence into ''γ''-carboxyglutamate <ref>PMID:8530480</ref>. | ||
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http://www.natuurlijkerwijs.com/english/ ]] | http://www.natuurlijkerwijs.com/english/ ]] | ||
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<span style="color:Brown">'''''γ''-Carboxylation Reaction'''</span> is catalyzed by the γ-glutamyl carboxylase in the ER and requires a reduced form of vitamin K, oxygen, and carbon dioxide<ref>PMID:10068650</ref>. The reaction is initiated by the removal of a hydrogen atom at the γ position of glutamate. This reaction creates a carbon ion that reacts with carbon dioxide thus forming γ-carboxy glutamic acid. As the protein is carboxylated using carbon dioxide the reduced vitamin K (hydroquinone) is oxidized to epoxide. | <span style="color:Brown">'''''γ''-Carboxylation Reaction'''</span> is catalyzed by the γ-glutamyl carboxylase in the ER and requires a reduced form of vitamin K, oxygen, and carbon dioxide<ref>PMID:10068650</ref>. The reaction is initiated by the removal of a hydrogen atom at the γ position of glutamate. This reaction creates a carbon ion that reacts with carbon dioxide thus forming γ-carboxy glutamic acid. As the protein is carboxylated using carbon dioxide the reduced vitamin K (hydroquinone) is oxidized to epoxide. | ||
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The catalytic domain of FIX is composed of two β-<scene name='Factor_IX/Rfnscene/3'>barrel</scene> subdomains that form an active site at their interface. The active site is located at the junction of these β-barrels. The EGF-2 domain is connected to the catalytic domain through a disulfide bridge and is opposite to the active site. There are three disulfide bonds, and the C-terminus contains helical structures that run across the N-terminus of the β-barrel. The catalytic domain contains a calcium binding site that exposes the <scene name='Factor_IX/Rfnscene_5/1'>148-loop</scene> for proteolytic cleavage. This calcium ion is stabilized by Glu-70, Glu-77, Glu-80 and a main chain oxygens of Asn-72 and Glu-75. This site seems to be preformed, unlike the calcium binding sites that are generated in the Gla domain upon calcium binding. | The catalytic domain of FIX is composed of two β-<scene name='Factor_IX/Rfnscene/3'>barrel</scene> subdomains that form an active site at their interface. The active site is located at the junction of these β-barrels. The EGF-2 domain is connected to the catalytic domain through a disulfide bridge and is opposite to the active site. There are three disulfide bonds, and the C-terminus contains helical structures that run across the N-terminus of the β-barrel. The catalytic domain contains a calcium binding site that exposes the <scene name='Factor_IX/Rfnscene_5/1'>148-loop</scene> for proteolytic cleavage. This calcium ion is stabilized by Glu-70, Glu-77, Glu-80 and a main chain oxygens of Asn-72 and Glu-75. This site seems to be preformed, unlike the calcium binding sites that are generated in the Gla domain upon calcium binding. | ||
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==3D structures of factor IX== | ==3D structures of factor IX== | ||
