Sandbox Reserved 1725: Difference between revisions

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[[Image:Vitamin_K_Cycle_2.jpg|300 px|left|thumb|'''Figure 1. Vitamin K Cycle''' λ-glutamyl

carboxylase uses Vitamin KH2 to carboxylate blood clotting cofactors, converting KH2 to KO in the process. Prothrombin is shown as an example of a blood clotting cofactor that later enters the coagulation cascade. VKOR converts KO back to KH2 via two steps with Vitamin K as an intermediate.]]

[[Image:~~barrel_domain_smaller~~.~~jpg~~|200 px|right|thumb|'''Figure 2. VKOR ~~with Barrel Domain~~''' The teal helices are the transmembrane helices situated in the ER membrane. The tan sections are the beta loop and cap loop. The light blue section is the cap helix, and the dark blue section is the anchor. The cap loop, cap helix, and anchor make up the cap domain. The white barrel domain was used for stabilization during structural experiments and is not shown in future scenes on this page.]]

[[Image:vkor_crop.png|200 px|right|thumb|'''Figure 2. VKOR Overview''' The teal helices are the transmembrane helices situated in the ER membrane. The tan sections are the beta loop and cap loop. The light blue section is the cap helix, and the dark blue section is the anchor. The cap loop, cap helix, and anchor make up the cap domain. The white barrel domain was used for stabilization during structural experiments and is not shown in future scenes on this page.]]

=== Vitamin K Cycle ===

[https://en.wikipedia.org/wiki/Vitamin_K Vitamin K] is essential for [https://en.wikipedia.org/wiki/Coagulation#Coagulation_cascade blood clotting] in the body<ref name="Stafford">PMID:16102054</ref>. The fully reduced form, KH2, is used by [https://en.wikipedia.org/wiki/Gamma-glutamyl_carboxylase#:~:text=Gamma-glutamyl%20carboxylase%20is%20an%20enzyme%20that%20catalyzes%20the,of%20the%20encoded%20enzyme%20is%20essential%20for%20hemostasis gamma-glutamyl carboxylase] to carboxylate protein-bound glutamate residues in blood clotting cofactor precursors <ref name="Blanchard">PMID:6165889</ref>. After carboxylation, the clotting cofactors (such as [https://proteopedia.org/wiki/index.php/Thrombin prothrombin]) can bind to calcium and can proceed to the coagulation cascade <ref name="Swanson">PMID:6758841</ref>. During this process, KH2 becomes oxidized to Vitamin K epoxide, or KO <ref name="Blanchard">PMID:6165889</ref>. Vitamin K epoxide reductase, abbreviated VKOR, turns the epoxide back to the fully reduced form so the reduced form can be used again. This transformation happens in two steps: 1) converting the epoxide to the partially oxidized Vitamin K quinone and 2) converting the quinone to the fully reduced hydroquinone (KH2) (Figure 1) <ref name="Stafford">PMID:16102054</ref>.

Sandbox Reserved 1725: Difference between revisions

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@@ Line 7: / Line 7: @@
 [[Image:Vitamin_K_Cycle_2.jpg|300 px|left|thumb|'''Figure 1. Vitamin K Cycle''' λ-glutamyl
 carboxylase uses Vitamin KH2 to carboxylate blood clotting cofactors, converting KH2 to KO in the process. Prothrombin is shown as an example of a blood clotting cofactor that later enters the coagulation cascade. VKOR converts KO back to KH2 via two steps with Vitamin K as an intermediate.]]
-[[Image:barrel_domain_smaller.jpg|200 px|right|thumb|'''Figure 2. VKOR with Barrel Domain''' The teal helices are the transmembrane helices situated in the ER membrane. The tan sections are the beta loop and cap loop. The light blue section is the cap helix, and the dark blue section is the anchor. The cap loop, cap helix, and anchor make up the cap domain. The white barrel domain was used for stabilization during structural experiments and is not shown in future scenes on this page.]]
+[[Image:vkor_crop.png|200 px|right|thumb|'''Figure 2. VKOR Overview''' The teal helices are the transmembrane helices situated in the ER membrane. The tan sections are the beta loop and cap loop. The light blue section is the cap helix, and the dark blue section is the anchor. The cap loop, cap helix, and anchor make up the cap domain. The white barrel domain was used for stabilization during structural experiments and is not shown in future scenes on this page.]]
 === Vitamin K Cycle ===
 [https://en.wikipedia.org/wiki/Vitamin_K Vitamin K] is essential for [https://en.wikipedia.org/wiki/Coagulation#Coagulation_cascade blood clotting] in the body<ref name="Stafford">PMID:16102054</ref>. The fully reduced form, KH2, is used by [https://en.wikipedia.org/wiki/Gamma-glutamyl_carboxylase#:~:text=Gamma-glutamyl%20carboxylase%20is%20an%20enzyme%20that%20catalyzes%20the,of%20the%20encoded%20enzyme%20is%20essential%20for%20hemostasis gamma-glutamyl carboxylase] to carboxylate protein-bound glutamate residues in blood clotting cofactor precursors <ref name="Blanchard">PMID:6165889</ref>. After carboxylation, the clotting cofactors (such as [https://proteopedia.org/wiki/index.php/Thrombin prothrombin]) can bind to calcium and can proceed to the coagulation cascade <ref name="Swanson">PMID:6758841</ref>. During this process, KH2 becomes oxidized to Vitamin K epoxide, or KO <ref name="Blanchard">PMID:6165889</ref>. Vitamin K epoxide reductase, abbreviated VKOR, turns the epoxide back to the fully reduced form so the reduced form can be used again. This transformation happens in two steps: 1) converting the epoxide to the partially oxidized Vitamin K quinone and 2) converting the quinone to the fully reduced hydroquinone (KH2) (Figure 1) <ref name="Stafford">PMID:16102054</ref>.