Sandbox Reserved 895: Difference between revisions
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[[Image:RPE65_Figure5_Binding_Pocket.jpg|thumb|center|512 px|alt=Figure 5: RPE65 Binding Pocket| '''Figure 5:''' RPE65 Binding Pocket <ref> DOI 19805034 </ref>]] | [[Image:RPE65_Figure5_Binding_Pocket.jpg|thumb|center|512 px|alt=Figure 5: RPE65 Binding Pocket| '''Figure 5:''' RPE65 Binding Pocket <ref> DOI 19805034 </ref>]] | ||
=== ''' [1.2.3] Proposed Enzymatic Mechanism of RPE65''' === | |||
From an enzymatic point of view, RPE65 is similar to its carotenoid-cleaving relatives in that a ferrous ion is required for catalytic activity. Although the specific enzymatic mechanism for RPE65 is complex and not well elucidated, previous research has shown that the most probable reaction mechanism is as shown in '''Figure 6A''' and '''Figure 6B'''. The initial interaction with the ester moiety of all-trans-retinyl ester with the ferrous ion polarizes the carbon-15 oxygen σ (sigma) bond and makes the fatty ester an activated leaving group. Formation of a resonance-stabilized carbocation reduces the π (pi) bond order of the system allowing temporary rotation about the carbon-11, carbon-12 σ bond. A water molecule obtained from the bulk solution attacks the carbon-15 atom quenching the carbocation intermediate. Finally, the protonation of the fatty acid carboxylate group promotes its dissociation from the ion cofactor. This process releases the fatty acid and the now 11-cis-retinol from the active site of RPE65. <ref> DOI 19805034 </ref> | |||
[[Image:RPE65_Figure6_Reacation_mechanism.jpg|thumb|center|512 px|alt=Figure 5: RPE65 Hypothesized Reaction Mechanism| '''Figure 6:''' (A) All-''trans''-retinol (B) Hypothesized RPE65 Reaction Mechanism <ref> DOI 19805034 </ref>]] | |||
= References = | = References = | ||
<references/> | <references/> | ||
