Name: Papain

Synonyms: Velardon; Vermizym

CAS Registry Number: 9001-73-4

EINECS: 232-627-2

Papain is a cysteine protease (EC 3.4.22.2) hydrolase 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. Asn-158 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.
Its utility is in breaking down tough meat fibers and has been utilized for thousands of years in its native South America. It is sold as a component in powdered meat tenderizer available in most supermarkets. Papain, in the form of a meat tenderizer such as Adolph´s, made into a paste with water, is also a home remedy treatment for jellyfish, bee, yellow jacket (wasps) stings, mosquito bites, and possibly stingray wounds, breaking down the protein toxins in the venom. It is also the main ingredient in Stop Itch and Stop Itch Plus, a DermaTech Laboratories first aid cream popular in Australia.
Papain is used to dissociate cells in the first step of cell culture preparations. A 10-minute treatment of small tissue pieces (less than 1 mm cubed) will allow papain to begin breaking down the extracellular matrix molecules holding the cells together. After 10 minutes, the tissue should be treated with a protease inhibitor solution to stop the protease action (if left untreated papain´s activity will lead to complete lysis of the cells). The tissue must then be triturated (passed quickly up and down through a Pasteur pipette) in order to break up the pieces of tissue into a single cell suspension.

Test Items	Specifications
Appearance	White or Light yellow Powder
Odor	Free of offensive odours
Activity of enzyme	800 000 u/g
Solubility	100% solution
Particle Size	80 mesh
Ash	12%Max
Moisture	8% Max
Coliform (MPH/100g)	30 Max
Bacteria	None detected
Heavy metals(as Pb)	2.0mg/kg Max
Heavy metals(as As)	2.0mg/kg Max

Packing:25kg/drum