Josie N. Harmon/Sandbox Tutorial
From Proteopedia
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One side of the xanthine oxidoreductase enzyme consists of an active site that includes a molybdenum atom which binds to a purine substrate and adds a hydroxyl group. During this process electrons are extracted and funneled from the active site through a string of iron-sulfur clusters to the opposing side of the enzyme. The opposing side then transfers the electrons to NAD or oxygen depending on the dehydrogenase or oxidase nature of the enzyme. One of the final steps in the electron transfer funnels electrons to a FAD group. The dehydrogenase form of the enzyme transfers these electrons to NAD, while the oxidase form blocks NAD through a loop of protein that covers the FAD molecule allowing smaller oxygen molecules to accept the electrons. | One side of the xanthine oxidoreductase enzyme consists of an active site that includes a molybdenum atom which binds to a purine substrate and adds a hydroxyl group. During this process electrons are extracted and funneled from the active site through a string of iron-sulfur clusters to the opposing side of the enzyme. The opposing side then transfers the electrons to NAD or oxygen depending on the dehydrogenase or oxidase nature of the enzyme. One of the final steps in the electron transfer funnels electrons to a FAD group. The dehydrogenase form of the enzyme transfers these electrons to NAD, while the oxidase form blocks NAD through a loop of protein that covers the FAD molecule allowing smaller oxygen molecules to accept the electrons. | ||
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| + | == Clinical application == | ||
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| + | == Xanthine oxidase inhibitors == | ||
| + | Xanthine oxidase inhibitors act by inhibiting the activity of the enzyme, namely its purine metabolism activity. Inhibitors of the enzyme are commonly used in the treatment of hyperuricemia, and its corresponding medical conditions such as gout, by reducing the production of uric acid. Currently there is also investigation of the use of xanthine oxidase inhibitors in the prevention and treatment of cardiovascular and cerebrovascular disease. As previously mentioned xanthine oxidase plays an important role in purine degradation with the last step in this process resulting in the production of uric acid to be excreted from the body. This excretion; however, is not always an efficient process and there can be an abnormal accumulation of uric acid in the blood. This accumulation can come as a result of increased production by the way of a purine rich diet, decreased excretion by the way of drug interactions or genetics, or a combination of the two. The most common type of xanthine oxidase inhibitors are classified as purine analogues and consists of allopurinol and oxypurinol. | ||
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</StructureSection> | </StructureSection> | ||
[[Image:Xanthine_oxidase_reaction.png]] | [[Image:Xanthine_oxidase_reaction.png]] | ||
Revision as of 19:03, 7 November 2012
Xanthine Oxidase Biochemistry Tutorial
The human diet introduces a large assortment of various new molecules into the body. These molecules are often degraded and used by the body to be later utilized as a source of metabolic energy. In other cirmcumstances the molecules can be broken down into components to be used by the body to build necessary proteins and nucleic acids. Lastly, any molecules that are remaining following the previous processes can be degraded for elimination. Xanthine oxidoreductase is considered to be the final stop for extra purine nucleotides, such as adenosine triphosphate (ATP)Image:ATP.pngand guanosine triphosphate (GTP)Image:GTP.png, in our cells. Inside the cells the enzyme takes on a role of purine degredation, where it is involved in the extrememly inportant catabolism of purines through a series of steps to yield uric acid which is ultimately excreted from the body.
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