Papain By Junaid ikram

Papain:-

Papain, also known as papaya proteinase I,

Is a cysteine protease enzyme present in papaya (Carica papaya) and mountain papaya.

STRUCTURE:

The globular protein, the papain is a single chain protein with molecular weight of 23,406 DA and consists of 212 amino acid with four disulphide bridges.

Papain family:-

Papain belongs to a family of related proteins with a wide variety of activities, including endopeptidases, aminopeptidases, dipeptidyl peptidases and enzymes with both exo- and endo-peptidase activity.

Members of the papain family are widespread, found in baculoviruses, eubacteria, yeast, and practically all protozoa, plants and mammals.

The proteins are typically lysosomal or secreted, and proteolytic cleavage of the propeptide is required for enzyme activation, although bleomycin hydrolase is cytosolic in fungi and mammals.

Papain-like cysteine proteinases are essentially synthesised as inactive proenzymes (zymogens) with N-terminal propeptide regions.

The activation process of these enzymes includes the removal of propeptide regions, which serve a variety of functions in vivo and in vitro.

Amino acid residues within the pro-region mediate their membrane association, and play a role in the transport of the proenzyme to lysosomes.

Among the most notable features of propeptides is their ability to inhibit the activity of their cognate enzymes and that certain propeptides exhibit high selectivity for inhibition of the peptidases from which they originate.

Isolation of papain

The full grown but unripe fruit is subjected to shallow incisions on the four sides.The latex flows freely for a few seconds,but soon coagulates.After collection the coagulated lumps are shredded and dried by the sun or byBy the use of artificial heat.Incisions and collections are made at weekly intervals as long as the fruit exudes the latex.The crude papin is purified by dissolving in the water and precipitating with alchohol.

Chemical constituents:

Papain contain several enzymes Peptidase: capable of converting into

dipeptides and poly piptides. A renin like coagulation enzyme that acts on

the casein of milk An amylolytic enzyme which converts

carbohydrates molecules into simple units.

Function:- The mechanism by which papain breaks peptide

bonds involves the use of a catalytic triad with a deprotonated cystine.

This cysteine then performs a nucleophilic attack on the carbonyl carbon of a peptide backbone.

This forms a covalent acyl-enzyme intermediate and frees the amino terminus of the peptide

The enzyme is deacylated by a water molecule and releases the carboxy terminal portion of the peptide.

Papain is a relatively heat-resistant enzyme, with an optimal temperature range of 60 and 70 °C.

Developed the technical knowhow for the product. The process flow chart is as under.

Collection of latex

Cleaning and

sieving

Mixing and

drying

Packing

Uses:- Papain breaks down tough meat fibres.

Papain can be used to dissociate cells in the first step of cell culture preparations.

A ten-minute treatment of small tissue pieces (less than 1 mm cubed) will allow papain to begin cleaving the extracellular matrix molecules holding the cells together.

After ten minutes, the tissue should be treated with a protease inhibitor solution to stop the protease action.

Left untreated, papain activity will lead to complete lysis of the cells.

The tissue must then be triturated (passed quickly up and down through a Pasteur pipette) to break up the pieces of tissue into a single cell suspension.

Papain is the main ingredient of Papacarie, a gel used for chemomechanical dental caries removal.

It does not require drilling and does not interfere in the bond strength of restorative materials to dentin.

Papain has been known to interfere with urine drug tests for cannabinoids.

It is found in some drug detox products.

Production;- Papain is usually produced as a crude,

dried material by collecting the latex from the fruit of the papaya tree.

The latex is collected after scoring the neck of the fruit, where it may either dry on the fruit or drip into a container.

This latex is then further dried. It is now classified as a dried, crude material.

A purification step is necessary to remove contaminating substances.

This purification consists of the solubilization and extraction of the active papain enzyme system through a government-registered process.

This purified papain may be supplied as powder or as liquid.