Papain is a low specificity proteolytic enzyme. It is widely found in the roots, stems, leaves and fruits of papaya, and has the highest content in immature latex. Papain is a sulfhydryl protease, and its active site contains cysteine, which has the characteristics of high enzymatic activity, high thermal stability and safety. Therefore, it is widely used in the food, medicine, feed, chemical, cosmetic, leather and textile industries.
Papain is a low specificity proteolytic enzyme. It is widely found in the roots, stems, leaves and fruits of papaya, and has the highest content in immature latex. Papain is a sulfhydryl protease, and its active site contains cysteine, which has the characteristics of high enzymatic activity, high thermal stability and high safety. Therefore, it is widely used in the food, medicine, feed, chemical, cosmetic, leather and textile industries.
The role of papain
The immature papaya fruit contains a variety of proteolytic enzymes such as papain, chymotrypsin A, chymotrypsin B, and papain B. It is known that the primary structures of the four cysteine proteases have a high degree of homology. Among them, papain is a sulfhydryl protease, which can hydrolyze the carboxyl end of arginine and lysine in proteins and polypeptides. And can preferentially hydrolyze those amino acids with two carboxyl groups or aromatic L-amino acids at the N-terminus of the peptide bond.
Papain is a proteolytic enzyme with a molecular weight of 23.4 kDa, composed of a single peptide chain, containing 212 amino acid residues. There are at least three amino acid residues in the active center of the enzyme. They are Cys25, His159 and Asp158. When Cys25 is oxidized by oxidants or combined with metal ions, the activity of the enzyme is inhibited, while the reducing agent cysteine (or sulfite) or EDTA can restore the activity of the enzyme. The other six cysteine residues form three pairs of disulfide bonds, and none of them are in the active site. Pure papain products can contain: (1) papain, with a molecular weight of 21 kDa, accounting for about 10% of soluble protein. (2) Papaya chymotrypsin has a molecular weight of 26 kDa and accounts for about 45% of soluble protein. (3) Lysozyme, with a molecular weight of 25 kDa, accounts for about 20% of soluble protein, and different enzymes such as cellulase.
Application areas of papain
The use of papain is very extensive, and the methods of use are also diversified. Creative Enzymes provides high-quality papain that can meet your different needs.
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