Papain: Difference between revisions
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[[Image:papayas.jpg|525px|right|thumb|Papaya<ref>[http://dailyfitnessmagz.com/2011/03/papayas-nutrition-facts/] Papaya's Nutrition Facts</ref>]] | [[Image:papayas.jpg|525px|right|thumb|Papaya<ref>[http://dailyfitnessmagz.com/2011/03/papayas-nutrition-facts/] Papaya's Nutrition Facts</ref>]] | ||
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== Introduction == | == Introduction == | ||
'''Papain'''. Meat tenderizer. Old time home remedy for insect, jellyfish, and stingray stings<ref>[http://www.ameriden.com/products/advanced-digestive-enzyme/] Ameridan International</ref>. Who would have thought that a sulfhydryl protease from the latex of the papaya fruit, ''Carica papaya'' and ''Vasconcellea cundinamarcensis'', would have such a practical application beyond Proteopedia? | |||
Papain is a 23.4 kDa, 212 residue cysteine protease, also known as '''papaya proteinase I''', from the peptidase C1 family ([[EC Number|E.C.]] [[Hydrolase|3.4.22.2]]).<ref>[http://www.uniprot.org/uniprot/P00784] Uniprot</ref><ref name="9PAP PDB">[http://www.pdb.org/pdb/explore/explore.do?structureId=9PAP] 9PAP PDB</ref> It is the natural product of the [http://en.wikipedia.org/wiki/Carica_papaya Papaya](''Carica papaya'')<ref name="Sigma Aldrich">[http://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/analytical-enzymes/papain.html] Sigma Aldrich</ref>, and may be extracted from the plant's latex, leaves and roots. Papain displays a broad range of functions, acting as an endopeptidase, exopeptidase, amidase, and esterase,<ref name="Worthington">[http://www.worthington-biochem.com/pap/default.html] Worthington</ref> with its optimal activity values for pH lying between 6.0 and 7.0, and its optimal temperature for activity is 65 °C. Its pI values are 8.75 and 9.55, and it is best visualized at a wavelength of 278 nm. <ref name="Sigma Aldrich" /> | Papain is a 23.4 kDa, 212 residue cysteine protease, also known as '''papaya proteinase I''', from the peptidase C1 family ([[EC Number|E.C.]] [[Hydrolase|3.4.22.2]]).<ref>[http://www.uniprot.org/uniprot/P00784] Uniprot</ref><ref name="9PAP PDB">[http://www.pdb.org/pdb/explore/explore.do?structureId=9PAP] 9PAP PDB</ref> It is the natural product of the [http://en.wikipedia.org/wiki/Carica_papaya Papaya](''Carica papaya'')<ref name="Sigma Aldrich">[http://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/analytical-enzymes/papain.html] Sigma Aldrich</ref>, and may be extracted from the plant's latex, leaves and roots. Papain displays a broad range of functions, acting as an endopeptidase, exopeptidase, amidase, and esterase,<ref name="Worthington">[http://www.worthington-biochem.com/pap/default.html] Worthington</ref> with its optimal activity values for pH lying between 6.0 and 7.0, and its optimal temperature for activity is 65 °C. Its pI values are 8.75 and 9.55, and it is best visualized at a wavelength of 278 nm. <ref name="Sigma Aldrich" /> | ||
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There are a small number of <scene name='Papain/Stefin_b_hbonds/2'>direct hydrogen bonds</scene> (labeled in <scene name='Papain/Stefin_b_hbonds/1'>this scene</scene>, between Stefin B and Papain, however there are many more polar interactions mediated by <scene name='Papain/Stfn_b_solvent_intrxns/1'>solvent bridges</scene>, the solvent being mainly <big><b><font color='darkturquoise'>water</font></b></big>. Thirteen solvent molecules of water bridge polar residues of the enzyme and inhibitor. Seventeen hydrogen bonds are made with a solvent molecule and Stefin B. Fourteen of these bridges form a Papain contact. The rest of the interactions are largely hydrophobic-- involving apolar <scene name='Papain/Stefin_b_vdw/2'>Van der Waals forces</scene>.<ref> PMID:2347312 </ref> | There are a small number of <scene name='Papain/Stefin_b_hbonds/2'>direct hydrogen bonds</scene> (labeled in <scene name='Papain/Stefin_b_hbonds/1'>this scene</scene>, between Stefin B and Papain, however there are many more polar interactions mediated by <scene name='Papain/Stfn_b_solvent_intrxns/1'>solvent bridges</scene>, the solvent being mainly <big><b><font color='darkturquoise'>water</font></b></big>. Thirteen solvent molecules of water bridge polar residues of the enzyme and inhibitor. Seventeen hydrogen bonds are made with a solvent molecule and Stefin B. Fourteen of these bridges form a Papain contact. The rest of the interactions are largely hydrophobic-- involving apolar <scene name='Papain/Stefin_b_vdw/2'>Van der Waals forces</scene>.<ref> PMID:2347312 </ref> | ||
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