Sandbox 38: Difference between revisions
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[[Image:Papainmech6.jpg|200px|left|thumb|mechanism of Papain <ref>[http://chemistry.umeche.maine.edu/CHY431/Peptidase10.html] University of Maine</ref>.]] | [[Image:Papainmech6.jpg|200px|left|thumb|mechanism of Papain <ref>[http://chemistry.umeche.maine.edu/CHY431/Peptidase10.html] University of Maine</ref>.]] | ||
This hydrolytic enzyme is able to break peptide bonds through the deprotonation of Cys-25 by His-159, with the help of Aspartate-125, which stabilizes the Histadine ring in order for this deprotonation to take place. The Cys-25 residue is then able to perform a nucleophilic attack on the carbonyl carbon of the peptide backbone, freeing the amino terminal of the peptide, forming a covalent intermediate. Next, the enzyme is deacylated by water, and the carboxy-terminal portion of the peptide is released. | This hydrolytic enzyme is able to break peptide bonds through the deprotonation of Cys-25 by His-159, with the help of Aspartate-125, which stabilizes the Histadine ring in order for this deprotonation to take place. The Cys-25 residue is then able to perform a nucleophilic attack on the carbonyl carbon of the peptide backbone, freeing the amino terminal of the peptide, forming a covalent intermediate. Next, the enzyme is deacylated by water, and the carboxy-terminal portion of the peptide is released. | ||
