Sandbox 36
From Proteopedia
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==Catalytic Diad== | ==Catalytic Diad== | ||
| - | The <scene name='Sandbox_36/Papain_active_site_use/2'>active site</scene> is located in the cleft between the two domains. The active site contains a catalytic diad made up of Cysteine-25 and Histidine-159. Aspartate-158 also plays a role in catalysis. Papain's active site can accommodate seven amino acids of a substrate. When the peptide is cleaved, the first four resides reside on the amino side of the peptide bond while the other three reside on the carboxyl side. | + | The <scene name='Sandbox_36/Papain_active_site_use/2'>active site</scene> is located in the cleft between the two domains. The active site contains a <scene name='Sandbox_36/Papain_catalytic_diad/1'>catalytic diad</scene> made up of Cysteine-25 and Histidine-159. Aspartate-158 also plays a role in catalysis but it is not considered part of the diad. Papain's active site can accommodate seven amino acids of a substrate. When the peptide is cleaved, the first four resides reside on the amino side of the peptide bond while the other three reside on the carboxyl side. |
Revision as of 05:13, 12 November 2011
| Please do NOT make changes to this Sandbox. Sandboxes 30-60 are reserved for use by Biochemistry 410 & 412 at Messiah College taught by Dr. Hannah Tims during Fall 2012 and Spring 2013. |
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Contents |
Papain
Introduction
Papain is a sulfhydryl protease derived from the papaya fruit. Papain has many varied and important commercial uses. It is often used as a meat tenderizer because it can hydrolyze the peptide bonds of collagen, elastin, and actomyosin. It is also used in contact lens solution to remove protein deposits on the lenses. Papain also has many medical uses and is used to treat pain, swelling, and fluid retention following trauma and surgery. More commonly, papain is used as a digestive supplement.
Structure
Papain consists of a single polypeptide chain of 212 amino acid residues. As with all proteins, folding to form secondary and tertiary structures is largely determined by the interactions of the to exclude water. 55 of these residues form 7 and 45 residues form 17 strands. Besides these structures, the secondary structure of papain is irregular. The protein's tertiary structure consists of two domains divided by a cleft in which the active site resides.
Catalytic Diad
The is located in the cleft between the two domains. The active site contains a made up of Cysteine-25 and Histidine-159. Aspartate-158 also plays a role in catalysis but it is not considered part of the diad. Papain's active site can accommodate seven amino acids of a substrate. When the peptide is cleaved, the first four resides reside on the amino side of the peptide bond while the other three reside on the carboxyl side.
