Merck, 76216-250MG, Papain from Carica papaya

General description
Papain is a proteolytic enzyme and is naturally occurring in papaya (Carica papaya L.). It is obtained from the latex of cut unripe papaya. Papain belongs to the cysteine proteinase family. It is a globular, single-chain protein composed of four disulfide bridges and catalytically essential residues. Papain consists of an all α-domain and anti-parallel β-sheet domain.
Application
Papain is used as a meat tenderizer. It′s also used to break up tissue in the preparation of primary cell cultures.
Papain from Carica papaya has been used:

in the enzymatic dissociation of rat cortices to extract astrocytes for cell culture
to study its effects on Alpaca seminal plasma viscosity and sperm function
to study its effects on the yield and cryo-survival of Rhinoceros spermatozoa

Biochem/physiol Actions
Papain is a cysteine protease that cleaves peptide bonds and is known to cleave the Fc portion of antibodies.
Papain plays an important role in many biological processes in many living organisms. It exhibits proteolytic activity against proteins, amino-acid esters and amide links, and short-chain peptides. Papain preferentially cleaves the peptide bonds of basic amino acids such as arginine, phenylalanine, and lysine. It has a wide range of applications in drug discovery, pharmaceutical, food, baking, and dairy industries.
Other Notes
1 U corresponds to the amount of enzyme which hydrolyzes 1 μmol N-benzoyl-L-arginine ethyl ester (BAEE, Cat. No. 12880) per minute at pH 6.2 and 25°C