Sandbox 35: Difference between revisions

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The <scene name='Sandbox_35/Active_site_papain/3'>active site</scene> primarily consist of three main residues Cys25-His159-Asn175 that resemble the catalytic triad of chymotrypsin <ref>PMID: 8140097</ref><ref>PMID: 2397208</ref>. However growing studies are showing that the mechanism behind catalysis may actually involve a double catalytic site - consisting of Cys25-His159-Asn175 and Cys25-His159-<scene name='Sandbox_35/Active_site_asp_158_papain/1'>Asp 158</scene>! It is postulated that "a two-state mechanism" takes place instead of a "single steric mechanism." <ref>PMID: 8140097</ref> In addition, replacement of Asn 175 with other residues such as Ala mutants, reveals a decrease in kcat (less efficient), but the rate of hydrolysis was still significantly larger than non-catalytic rates suggesting a less essential role the residue plays than originally thought. <ref>[http://www.jbc.org/content/270/28/16645.abstract] The Journal of Biological Chemistry </ref>
The <scene name='Sandbox_35/Active_site_papain/4'>active site</scene> primarily consist of three main residues Cys25-His159-Asn175 that resemble the catalytic triad of chymotrypsin <ref>PMID: 8140097</ref><ref>PMID: 2397208</ref>. However growing studies are showing that the mechanism behind catalysis may actually involve a double catalytic site - consisting of Cys25-His159-Asn175 and Cys25-His159-
<scene name='Sandbox_35/Active_site_papain/5'>Asp 158</scene>! It is postulated that "a two-state mechanism" takes place instead of a "single steric mechanism." <ref>PMID: 8140097</ref> In addition, replacement of Asn 175 with other residues such as Ala mutants, reveals a decrease in kcat (less efficient), but the rate of hydrolysis was still significantly larger than non-catalytic rates suggesting a less essential role the residue plays than originally thought. <ref>[http://www.jbc.org/content/270/28/16645.abstract] The Journal of Biological Chemistry </ref>
    
    


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