Product name:Papain
CAS:9001-73-4
Specification:25G
Description:
Papain also known as papaya proteinase I is a cysteine protease (EC 3.4.22.2) enzyme present in papaya (Carica papaya) and mountain papaya (Vasconcellea cundinamarcensis).
The mechanism by which it breaks peptide bonds involves deprotonation of Cys-25 by His-159. Asparagine-175 helps to orient the imidazole ring of His-159 to allow this deprotonation to take place. Cys-25 then performs a nucleophilic attack on the carbonyl carbon of a peptide backbone. This frees the amino terminal of the peptide, and forms a covalent acyl-enzyme intermediate. The enzyme is then deacylated by a water molecule, and releases the carboxy terminal portion of the peptide. In immunology, papain is known to cleave the Fc (crystallisable) portion of immunoglobulins (antibodies) from the Fab (antigen-binding) portion.
Papain is relatively heat resistant enzyme.