Sandbox 33: Difference between revisions
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== Introduction == | == Introduction == | ||
Papain, also known as papaya proteinase I, is a cystaine protease enzyme in papaya (''Carica papaya'') and mountain papaya (''Vasconcellea cundinamarcensis'') | Papain, also known as papaya proteinase I, is a cystaine protease enzyme in papaya (''Carica papaya'') and mountain papaya (''Vasconcellea cundinamarcensis'')<ref>http://en.wikipedia.org/wiki/Papain</ref>. Papain is present in the leaves, latex, roots and fruit of the papaya plant <ref>http://www.britannica.com/EBchecked/topic/441803/papain</ref>. The latex of ''Carica papaya'' is a rich source of four cysteine endopeptidases including papain, chymopapain, glycyl endopeptidase, and caricain. The proteins are synthesized as inactive precursors that become active within two minutes of the plant being wounded and the latex expelled. Papain is a minor constituent, but it has been more widely studies because it is more easily purified <ref>http://www.worthington-biochem.com/pap/default.html</ref>. | ||
== History == | == History == | ||
Papain was first named in the late nineteenth century by Wurtz and Bouchut who partially purified the product from the sap of papaya. When named, it was simply recognized as proteolytically active constituent in the latex of tropical papaya fruit. | Papain was first named in the late nineteenth century by Wurtz and Bouchut who partially purified the product from the sap of papaya. When named, it was simply recognized as proteolytically active constituent in the latex of tropical papaya fruit. | ||
Throughout the mid 1950's and 1960's, purification and separation techniques improved greatly and pure papain was isolated. The study of papain allowed for great advances in understanding enzymes as proteins. In 1968, papin was the second enzyme to be crystallized and its structure determined by X-ray methods. Papain was the first cysteine protease to have its structure identified. | Throughout the mid 1950's and 1960's, purification and separation techniques improved greatly and pure papain was isolated. The study of papain allowed for great advances in understanding enzymes as proteins. In 1968, papin was the second enzyme to be crystallized and its structure determined by X-ray methods. Papain was the first cysteine protease to have its structure identified. | ||
In the 1980's, the geometry of the active site was reviewed and the three-dimensional structure was determined to a 1.65 Angstrom resolution. The precursors and inhibitors of papain were extensively studied into the 1990's. Today's research aims to further understand the specificity and structural perturbations brought about by inhibitors, low pH, metal ions, and fluorinated alcohols. | In the 1980's, the geometry of the active site was reviewed and the three-dimensional structure was determined to a 1.65 Angstrom resolution. The precursors and inhibitors of papain were extensively studied into the 1990's. Today's research aims to further understand the specificity and structural perturbations brought about by inhibitors, low pH, metal ions, and fluorinated alcohols<ref>http://www.worthington-biochem.com/pap/default.html</ref>. | ||
