Sandbox Reserved 918: Difference between revisions
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===Active Site=== | ===Active Site=== | ||
These substrates, along with many others, are cleaved by DPP IV using an active site containing a [http://en.wikipedia.org/wiki/Catalytic_triad catalytic triad] composed of <scene name='57/573132/1x70_catalytictriad/1'>Ser630, His740, and Asp708</scene>. This Serine-Histidine-Asparatate motif, best known in the enzyme [http://en.wikipedia.org/wiki/Chymotrypsin chymotrypsin], uses acid-base chemistry to facilitate the binding, cleaving, and release of the given substrate. The mechanism of the reaction is as follows: | These substrates, along with many others, are cleaved by DPP IV using an active site containing a [http://en.wikipedia.org/wiki/Catalytic_triad catalytic triad] composed of <scene name='57/573132/1x70_catalytictriad/1'>Ser630, His740, and Asp708</scene>. This Serine-Histidine-Asparatate motif, best known in the enzyme [http://en.wikipedia.org/wiki/Chymotrypsin chymotrypsin], uses acid-base chemistry to facilitate the binding, cleaving, and release of the given substrate.<ref name="Gorrell"/> The mechanism of the reaction is as follows: | ||
<div style="text-align: left;"> | <div style="text-align: left;"> | ||
# Substrate binds to enzyme and carbonyl carbon is positioned by [http://en.wikipedia.org/wiki/Active_site active site]. | # Substrate binds to enzyme and carbonyl carbon is positioned by [http://en.wikipedia.org/wiki/Active_site active site]. | ||
# Histidine, via hydrogen bond with asparatate, becomes more [http://en.wikipedia.org/wiki/Electronegativity electronegative] and therefore readily accepts the hydrogen from the | # Histidine, via hydrogen bond with asparatate, becomes more [http://en.wikipedia.org/wiki/Electronegativity electronegative] and therefore readily accepts the hydrogen from the hydroxyl group on serine, making it [http://en.wikipedia.org/wiki/Nucleophile nucleophilic]. [[Image:Serine_protease_mechanism_by_snellios.png|right|thumb|150px|<font size=".8"><div style="text-align: center;"> [[http://en.wikipedia.org/wiki/File:Serine_protease_mechanism_by_snellios.png Arrow Pushing Mechanism}} </div></font>]] | ||
# The nucleophilic serine attacks the [http://en.wikipedia.org/wiki/Carbonyl carbonyl] carbon, generating a [http://goldbook.iupac.org/T06289.html tetrahedral intermediate] (as seen in the [http://en.wikipedia.org/wiki/Arrow_pushing arrow pushing mechanism]). | # The nucleophilic serine attacks the [http://en.wikipedia.org/wiki/Carbonyl carbonyl] carbon, generating a [http://goldbook.iupac.org/T06289.html tetrahedral intermediate] (as seen in the [http://en.wikipedia.org/wiki/Arrow_pushing arrow pushing mechanism]). | ||
# The peptide bond is cleaved and the electrons from it move to attack the hydrogen on the histidine. This half of the substrate now dissociates, leaving the other half still bound to serine. | # The peptide bond is cleaved and the electrons from it move to attack the hydrogen on the histidine. This half of the substrate now dissociates, leaving the other half still bound to serine. | ||
