https://wiki.tiffa.net/w/index.php?action=history&feed=atom&title=Translations%3ACytochrome_P450%2F11%2Fen 2026-09-14T18:03:02Z Revision history for this page on the wiki MediaWiki 1.43.0 https://wiki.tiffa.net/w/index.php?title=Translations:Cytochrome_P450/11/en&diff=129036&oldid=prev 2024-03-15T11:35:28Z

<p>Importing a new version from external source</p> <p><b>New page</b></p><div>===Catalytic cycle===<br /> # Substrate binds in proximity to the [[heme group]], on the side opposite to the axial thiolate. Substrate binding induces a change in the conformation of the active site, often displacing a water molecule from the distal axial coordination position of the heme iron, and changing the state of the heme iron from low-spin to high-spin.<br /> # Substrate binding induces electron transfer from NAD(P)H via [[cytochrome P450 reductase]] or another associated [[reductase]].<br /> # Molecular oxygen binds to the resulting ferrous heme center at the distal axial coordination position, initially giving a [[transition metal dioxygen complex|dioxygen adduct]] similar to oxy-myoglobin.<br /> # A second electron is transferred, from either [[cytochrome P450 reductase]], [[ferredoxin]]s, or [[cytochrome b5|cytochrome b&lt;sub&gt;5&lt;/sub&gt;]], reducing the Fe-O&lt;sub&gt;2&lt;/sub&gt; adduct to give a short-lived peroxo state.<br /> # The peroxo group formed in step 4 is rapidly protonated twice, releasing one molecule of water and forming the highly reactive species referred to as &#039;&#039;&#039;P450 Compound 1&#039;&#039;&#039; (or just Compound I). This highly reactive intermediate was isolated in 2010, P450 Compound 1 is an iron(IV) oxo (or [[ferryl]]) species with an additional oxidizing equivalent [[delocalized]] over the [[porphyrin]] and thiolate ligands. Evidence for the alternative perferryl [[high-valent iron|iron(V)-oxo]] is lacking.<br /> # Depending on the substrate and enzyme involved, P450 enzymes can catalyze any of a wide variety of reactions. A hypothetical hydroxylation is shown in this illustration. After the product has been released from the active site, the enzyme returns to its original state, with a water molecule returning to occupy the distal coordination position of the iron nucleus.<br /> [[File:FeIVO 2.tif|thumb|left|[[Oxygen rebound mechanism]] utilized by cytochrome P450 for conversion of hydrocarbons to alcohols via the action of &quot;compound I&quot;, an iron(IV) oxide bound to a heme radical cation.|300px]]</div>

FuzzyBot