Sandbox Reserved 1058: Difference between revisions
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==Mechanism of Action== | ==Mechanism of Action== | ||
[[Image:Complete_Mechanism.PNG|500 px|right|thumb|'''Figure 5. Observed Mechanism for the Breakdown of Isocitrate by Isocitrate Lyase.''']] | [[Image:Complete_Mechanism.PNG|500 px|right|thumb|'''Figure 5. Observed Mechanism for the Breakdown of Isocitrate by Isocitrate Lyase.''']] | ||
His193 shifts the pKa of Cys191 and removes its proton. This allows Cys191 to extract a proton from the hydroxyl group of isocitrate. The resulting oxyanion forms a carbonyl and forces the lysis of a C-C bond. Glyoxylate and the enol form of succinate are formed and stabilized with a Mg<sup>2+</sup> ion. The succinate enolate resonates and extracts the proton back from Cys191 to form succinate ('''Figure 5'''). | Within isocitrate lyase, His193 shifts the pKa of Cys191 and removes its proton. This allows Cys191 to extract a proton from the hydroxyl group of isocitrate. The resulting oxyanion forms a carbonyl and forces the lysis of a C-C bond. Glyoxylate and the enol form of succinate are formed and stabilized with a Mg<sup>2+</sup> ion. The succinate enolate resonates and extracts the proton back from Cys191 to form succinate ('''Figure 5'''). | ||
