User:George G. Papadeas/Sandbox VKOR

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=== Catalytic Mechanism ===
=== Catalytic Mechanism ===
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[[Image:Catalytic Mech Pic.png |350 px|right| thumb]]
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[[Image:Catalytic Mech Pic.png |350 px| right| thumb]]
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The catalytic mechanism of VKOR is a critical part of its overall function in the body. Highly regulated enzymatic activity through the reactivity of catalytic cysteines allows VKOR to properly activate Vitamin K for its use in the body. The enzyme begins in <scene name='90/906893/Stage_1_catalytic_cycle/1'>stage 1</scene>, where it's in the open conformation with the cap domain open to allow in a substrate to bind to the active site. Once a substrate binds, the cap domain is initiated into the closed conformation. VKOR is now in <scene name='90/906893/Stage_2_catalytic_cycle/1'>stage 2</scene>. To further stabilize the closed conformation with the substrate bound, the cap domain helps initiate a catalytic reaction of cysteines to break the disulfide bridge that was stabilizing stage 1. Free cysteines are now available that provide strong stabilization of the closed conformation through interactions with the cap domain and the bound substrate. This puts the enzyme in <scene name='90/904314/Stage_3_catalytic_cycle/1'>Stage 3</scene>, where the catalytic free cysteines react to form a new disulfide bridge, releasing the activated substrate into the blood stream to promote anticoagulation. With two stable disulfide bridges and VKOR unbound, the enzyme is now in its final, unreactive <scene name='90/904314/Stage_4_catalytic_cycle/1'>Stage 4</scene>. VKOR must undergo conformational changes to return to Stage 1 and restart the catalytic process to activate Vitamin K again.
The catalytic mechanism of VKOR is a critical part of its overall function in the body. Highly regulated enzymatic activity through the reactivity of catalytic cysteines allows VKOR to properly activate Vitamin K for its use in the body. The enzyme begins in <scene name='90/906893/Stage_1_catalytic_cycle/1'>stage 1</scene>, where it's in the open conformation with the cap domain open to allow in a substrate to bind to the active site. Once a substrate binds, the cap domain is initiated into the closed conformation. VKOR is now in <scene name='90/906893/Stage_2_catalytic_cycle/1'>stage 2</scene>. To further stabilize the closed conformation with the substrate bound, the cap domain helps initiate a catalytic reaction of cysteines to break the disulfide bridge that was stabilizing stage 1. Free cysteines are now available that provide strong stabilization of the closed conformation through interactions with the cap domain and the bound substrate. This puts the enzyme in <scene name='90/904314/Stage_3_catalytic_cycle/1'>Stage 3</scene>, where the catalytic free cysteines react to form a new disulfide bridge, releasing the activated substrate into the blood stream to promote anticoagulation. With two stable disulfide bridges and VKOR unbound, the enzyme is now in its final, unreactive <scene name='90/904314/Stage_4_catalytic_cycle/1'>Stage 4</scene>. VKOR must undergo conformational changes to return to Stage 1 and restart the catalytic process to activate Vitamin K again.

Revision as of 15:22, 22 March 2022

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References

  1. Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:http://dx.doi.org/10.1002/ijch.201300024
  2. Herraez A. Biomolecules in the computer: Jmol to the rescue. Biochem Mol Biol Educ. 2006 Jul;34(4):255-61. doi: 10.1002/bmb.2006.494034042644. PMID:21638687 doi:10.1002/bmb.2006.494034042644

Proteopedia Page Contributors and Editors (what is this?)

George G. Papadeas

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