User:Adam Mirando/Sandbox 1: Difference between revisions

Line 16:

===Xanthine Dehydrogenase/Xanthine Oxidase Conversion===

Xanthine oxidoreductase has two functional forms: xanthine dehydrogenase and xanthine oxidase. This conversion is controlled by the oxidation state of Cys535, Cys992, and Cys1316. When these residues are reduced, the enzyme functions as a dehydrogenase, using NAD<sup>+</sup> as its final receptor. Following chemical modification (ie fluorodinitrobenzene) or oxidation (ie 4,4'-dithiopridine) the oxidase form is favored. Once oxidized, incubation with a reducing agent (ie dithiothreitol) will restore the enzyme to the the dehydrogenase form <ref name="conver" />. Studies involving the C535A/C992R/C1316S triple mutant, however, were unable to convert to the oxidase form <ref name="conver" />.

Xanthine oxidoreductase has two functional forms: xanthine dehydrogenase and xanthine oxidase. This conversion is controlled by the oxidation state of Cys535, Cys992, and Cys1316. When these residues are reduced, the enzyme functions as a dehydrogenase, using NAD<sup>+</sup> as its final receptor. Following chemical modification (ie fluorodinitrobenzene) or oxidation (ie 4,4'-dithiopridine) the oxidase form is favored. Once oxidized, incubation with a reducing agent (ie dithiothreitol) will restore the enzyme to the the dehydrogenase form <ref name="conver" />. Studies involving the C535A/C992R/C1316S triple mutant, however, were unable to convert to the oxidase form. Consequently, crystal structures of this mutant revealed a monomeric structure, in contrast to the normally homodimeric wild type enzyme <ref name="conver" />.

== Mechanism ==

@@ Line 16: / Line 16: @@
 ===Xanthine Dehydrogenase/Xanthine Oxidase Conversion===
-Xanthine oxidoreductase has two functional forms: xanthine dehydrogenase and xanthine oxidase. This conversion is controlled by the oxidation state of Cys535, Cys992, and Cys1316. When these residues are reduced, the enzyme functions as a dehydrogenase, using NAD<sup>+</sup> as its final receptor. Following chemical modification (ie fluorodinitrobenzene) or oxidation (ie 4,4'-dithiopridine) the oxidase form is favored. Once oxidized, incubation with a reducing agent (ie dithiothreitol) will restore the enzyme to the the dehydrogenase form <ref name="conver" />. Studies involving the C535A/C992R/C1316S triple mutant, however, were unable to convert to the oxidase form <ref name="conver" />.
+Xanthine oxidoreductase has two functional forms: xanthine dehydrogenase and xanthine oxidase. This conversion is controlled by the oxidation state of Cys535, Cys992, and Cys1316. When these residues are reduced, the enzyme functions as a dehydrogenase, using NAD<sup>+</sup> as its final receptor. Following chemical modification (ie fluorodinitrobenzene) or oxidation (ie 4,4'-dithiopridine) the oxidase form is favored. Once oxidized, incubation with a reducing agent (ie dithiothreitol) will restore the enzyme to the the dehydrogenase form <ref name="conver" />. Studies involving the C535A/C992R/C1316S triple mutant, however, were unable to convert to the oxidase form. Consequently, crystal structures of this mutant revealed a monomeric structure, in contrast to the normally homodimeric wild type enzyme <ref name="conver" />.
 == Mechanism ==