Sandbox 30
From Proteopedia
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==Overview== | ==Overview== | ||
| - | <applet load='9PAP' size='450' frame='true' align='right' scene='Sandbox_30/Papain_default/ | + | <applet load='9PAP' size='450' frame='true' align='right' scene='Sandbox_30/Papain_default/7' caption='Click on the links to the left to view different structural aspects. PDB code for this 1.65 Å resolution structure is 9PAP' /> |
Papain is a 23.4 kDa, 212 residue cysteine endopeptidase originating from the fruit of ''Carica papaya'', where it is present in significant amounts along with three other cysteine proteases, chymopapain, glycyl endopeptidase, and caricain<ref name="9PAP PDB">[http://www.pdb.org/pdb/explore/explore.do?structureId=9PAP] 9PAP PDB</ref><ref name="sigma">[http://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/analytical-enzymes/papain.html] Sigma Aldrich</ref><ref name="worthington">[http://www.worthington-biochem.com/pap/default.html] Worthington Biochemical Corporation</ref>. Its action was first described by G.C. Roy in 1873. It was studied intensively from the 1950s to the 1960s, during which time it became the second enzyme ever to have its structure determined by x-ray crystallography. Finally, high resolution structural analysis in the 1980s allowed an accurate description of the enzymes active site<ref name="worthington" />. As an enzyme, papain displays very wide hydrolase activity, serving as a general amidase and esterase in addition to its protease activity. As a protease, papain can hydrolyze bonds of basic amino acids, leucine, and glycine. It shows preference for residues preceded by a large hydrophobic residue, but will not cleave is valine is present on the carboxyl side of a potential cleavage site. In addition to being a very non-specific enzyme, papain is also unusually heat resistant, with maximal activity occurring at of 65° C. These properties have led to use of papain in a large variety areas. One of these areas is biological research, were papain is utilized in cell isolation. It is also useful in immunological techniques because of its ability to cleave the connection between the crystallizable fragment domain and the immunoglobulin domain in antibodies<ref name="sigma" />. Papain has also found use as an inflammation control agent, a digestive aid, and even a meat tenderizer<ref>[http://www.webmd.com/vitamins-supplements/ingredientmono-69-PAPAIN.aspx?activeIngredientId=69&activeIngredientName=PAPAIN] WebMD</ref>. | Papain is a 23.4 kDa, 212 residue cysteine endopeptidase originating from the fruit of ''Carica papaya'', where it is present in significant amounts along with three other cysteine proteases, chymopapain, glycyl endopeptidase, and caricain<ref name="9PAP PDB">[http://www.pdb.org/pdb/explore/explore.do?structureId=9PAP] 9PAP PDB</ref><ref name="sigma">[http://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/analytical-enzymes/papain.html] Sigma Aldrich</ref><ref name="worthington">[http://www.worthington-biochem.com/pap/default.html] Worthington Biochemical Corporation</ref>. Its action was first described by G.C. Roy in 1873. It was studied intensively from the 1950s to the 1960s, during which time it became the second enzyme ever to have its structure determined by x-ray crystallography. Finally, high resolution structural analysis in the 1980s allowed an accurate description of the enzymes active site<ref name="worthington" />. As an enzyme, papain displays very wide hydrolase activity, serving as a general amidase and esterase in addition to its protease activity. As a protease, papain can hydrolyze bonds of basic amino acids, leucine, and glycine. It shows preference for residues preceded by a large hydrophobic residue, but will not cleave is valine is present on the carboxyl side of a potential cleavage site. In addition to being a very non-specific enzyme, papain is also unusually heat resistant, with maximal activity occurring at of 65° C. These properties have led to use of papain in a large variety areas. One of these areas is biological research, were papain is utilized in cell isolation. It is also useful in immunological techniques because of its ability to cleave the connection between the crystallizable fragment domain and the immunoglobulin domain in antibodies<ref name="sigma" />. Papain has also found use as an inflammation control agent, a digestive aid, and even a meat tenderizer<ref>[http://www.webmd.com/vitamins-supplements/ingredientmono-69-PAPAIN.aspx?activeIngredientId=69&activeIngredientName=PAPAIN] WebMD</ref>. | ||
Revision as of 21:30, 7 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. |
Contents |
Papain
Overview
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Papain is a 23.4 kDa, 212 residue cysteine endopeptidase originating from the fruit of Carica papaya, where it is present in significant amounts along with three other cysteine proteases, chymopapain, glycyl endopeptidase, and caricain[1][2][3]. Its action was first described by G.C. Roy in 1873. It was studied intensively from the 1950s to the 1960s, during which time it became the second enzyme ever to have its structure determined by x-ray crystallography. Finally, high resolution structural analysis in the 1980s allowed an accurate description of the enzymes active site[3]. As an enzyme, papain displays very wide hydrolase activity, serving as a general amidase and esterase in addition to its protease activity. As a protease, papain can hydrolyze bonds of basic amino acids, leucine, and glycine. It shows preference for residues preceded by a large hydrophobic residue, but will not cleave is valine is present on the carboxyl side of a potential cleavage site. In addition to being a very non-specific enzyme, papain is also unusually heat resistant, with maximal activity occurring at of 65° C. These properties have led to use of papain in a large variety areas. One of these areas is biological research, were papain is utilized in cell isolation. It is also useful in immunological techniques because of its ability to cleave the connection between the crystallizable fragment domain and the immunoglobulin domain in antibodies[2]. Papain has also found use as an inflammation control agent, a digestive aid, and even a meat tenderizer[4].
Structure
The secondary structure of papain consists of 7 , 17 , all of which are antiparallel, and a large amount (about 50% of total residues) of . The , which goes from blue (amino terminus) to red (carboxyl terminus) is useful for tracing the order of these structures through the chain. Papain also contains three , which connect C22 to C63, C56 to C95, and C153 to C200[1]. These disulfide bonds are likely important in conserving the structural integrity of the enzyme as it operates in extracellular environments at high temperatures.
Residue Distribution
As can be seen from its , papain contains a variety of acidic (red), basic (blue), hydrophilic uncharged (pink), and hydrophobic (gray) residues. Since the enzyme operates in free solution, it would be expected that the hydrophilic residues would reside mostly on it exterior, shielding a hydrophobic core. This can be plainly seen from papain's , in which hydrophilic residues are purple and hydrophobic residues are grey. Upon removal of the hydrophilic residues, the of the enzyme is easy to see. As with all proteins, it is this hydrophobic segregation that allows the protein to properly fold and maintain a meaningful shape.
