Papain Inhibitor

Papain Inhibitor is a papain inhibitor, a cysteine protease found in papaya and mountain papaya. The mechanism of action is the cleavage of deprotonated Cys-25 peptide bonds by His-159. Asparagine-175 contributes to the imidazole ring orientation of His-159 and deprotonation occurs. Cys-25 attacks the carbonyl carbon of the peptide backbone, freeing the amino terminus of the peptide to form a covalent acylase intermediate. This enzyme deacylates through the water molecule and releases the carboxy-terminal portion of the peptide. It is well known that in immunology, papain cleaves the Fc moiety of Fab (antigen-binding) and immunoglobulins (antibodies). Papain tends to cleave between (hydrophobic)-(Arg or Lys) (not Val). Hydrophobic is Ala, Val, Leu, Ile, Phe, Trp, or Tyr. Papain isolates cells in the first step of cell culture. It can also be used as a component in various enzymatic debriding media, especially Accuzyme. These are some chronic wound care to remove necrotic tissue. Papain can also be used as an ingredient in some toothpastes or teeth whitening.