Papain

Химические свойства

cream to light brown powder

Использование

Papain may cause allergic manifestation .Person handling this material should be protected against inhalation of dust and contact with the skin or eyes.

прикладной

Papain (EC 3.4.22.2) is a protease derived from the latex portion of the papaya plant ( Carica papaya ), and is gathered by scoring the surface of the mature, unripe fruit, after which the latex is collected and dried (Schwimmer, 1981) . Drying can occur by one of several methods: sun, oven, or spray drying; end products having the highest activity are obtained by spray drying. Papain has broad-spectrum enzyme activity over a wide pH and temperature range, and it cleaves at basic amino acids or those having large hydrophobic side chains. Resulting peptides having terminal hydrophobic amino acids can result in a product with a bitter aftertaste. For this reason, papain is usually combined with other enzymes in the production of flavorings. Because papain is a thiol protease, oxidation of its cysteine residue under certain conditions can reduce the enzyme’s activity or potency. For this reason papain preparations often contain reducing agents such as sodium metabisulfite. Papain is economically available commercially in both liquid and powder forms. It has the longest history of use in meat systems and is the basis for some of the popular tenderizing sprinkle-on products that can be purchased by home consumers (Enzyme Development Corporation, 1999).

Определение

papain: A protein-digesting enzymeoccurring in the fruit of the West Indianpapaya tree (Carica papaya). It isused as a digestant and in the manufactureof meat tenderizers.

Общее описание

Papain (Papase), the dried and purifiedlatex of the fruit of Carica papaya L. (Caricaceae), can digestprotein in either acidic or alkaline media; it is best at a pH between4 and 7 and at 65°C to 90°C. It occurs as light brownishgray to weakly reddish brown granules, or as a yellowishgray to weakly yellow powder. It has a characteristic odor andtaste and is incompletely soluble in water to form an opalescentsolution. The commercial material is prepared by evaporatingthe juice, but the pure enzyme has also been preparedand crystallized. In medicine, it has been used locally in variousconditions similar to those for which pepsin is used. Ithas the advantage of activity over a wider range of conditions,but it is often much less reliable. Intraperitoneal instillation ofa weak solution has been recommended to counteract a tendencyto develop adhesions after abdominal surgery, and severalenthusiastic reports have been made about its value underthese conditions. Papain has been reported to cause allergiesin persons who handle it, especially those who are exposed toinhalation of the powder.

Профиль безопасности

Poison by intraperitoneal route. Human systemic effects by ingestion: changes in structure or function of esophagus. Experimental teratogenic and reproductive effects. An allergen. When heated to decomposition it emits toxic fumes of NOx.

Методы очистки

A suspension of 50g of papain (freshly ground in a mortar) in 200mL of cold water is stirred at 4o for 4hours, then filtered through a Whatman No 1 filter paper. The clear yellow filtrate is cooled in an ice-bath while a rapid stream of H2S is passed through it for 3hours, and the suspension is centrifuged at 2000rpm for 20minutes. Sufficient cold MeOH is added slowly with stirring to the supernatant to give a final MeOH concentration of 70 vol%. The precipitate, collected by centrifugation for 20minutes at 2000rpm, is then dissolved in 200mL of cold water, the solution is saturated with H2S, centrifuged, and the enzyme is again precipitated with MeOH. The process is repeated four times. [Bennett & Niemann J Am Chem Soc 72 1798 1950.] Papain has also been purified by affinity chromatography on a column of GlyGlyTyrArg-agarose [Stewart et al. J Am Chem Soc 109 3480 1986].