Chinese and English instructions of Papain

Papain is a sulfhydryl protease from Carica papaya latex. It has a molecular weight of 23 kDa and an optimum pH range of 6.0-7.0.  The action of papain on leucine methyl ester produces an insoluble polyleucine peptide. Papain breaks down the intercellular matrix of cartilage. Papain is activated by cysteine, sulfide, and sulfite. Stabilizing agents are EDTA, cysteine and dimercaptoethanol.

Stability/Storage: Stable for 6-12 months at 2-8°C.  Do not freeze aqueous suspensions.

Technical Notes: Papain preparations should be incubated in the activation solution before use to ensure full activity. Applications include antibody fragmentation and primary/neural cell isolation.

Unit Definition: One Unit hydrolyzes one micromole of benzoyl-L-arginine ethyl ester per minute at 25°C, pH 6.2, after activation in a solution containing 1.1 mM EDTA, 0.067 mM mercaptoethanol and 5.5 mM cysteine-HCl for 30 minutes.

Functional characteristics of Papain ：

Papain is mainly used for cold resistance of beer （ Hydrolyze the protein in beer , Avoid turbidity caused by cold storage ）、 Meat softening （ Hydrolyzed muscle protein and collagen , Soften meat ）、 Preparation of pre cooked cereals 、 Production of hydrolyzed protein and meat flavor . It is widely used in beer cold resistance and meat softening than other proteases .

AI Meijie Worthington Papain specificity ：

Papain has a wide range of specificity ; It has endopeptidase 、 Amidase and esterase activity . The active site consists of seven sub sites （S 1 -S 4 and  S 1' -S 3'） form , Each subunit can hold one amino acid residue of the substrate （P 1 -P 4 and  P 1' -P 3'）（Schechter And Berger  1967）. Specificity is determined by  S 2 Sub site control ,S 2  A subsite is a host substrate  P 2 Side chain hydrophobic bag . Papain exhibits a specific substrate preference , It is mainly due to a large number of hydrophobic or aromatic residues at this sub site （Kimmel  and  Smith 1954）. stay  S 2 Extra loci preference , Lack of well-defined residue selectivity within the active site .

Studies on papain ：

Collagenase  (CLS1-4/CLSPA)

Deoxyribonuclease  I (DP/D/DCLS/D2/DPFF/DPRF)

Hyaluronidase  (HSE/HSEP)

Neutral protease  (Dispase, NPRO)

protease  K (PROK)

Trypsin  (TL/TRL/TRL3/TRLS /TRTPCK)

Trypsin inhibitor  (LBI/OI/SI/SIC)

Cell separation optimization system  (CIT)

Hepatocyte isolation system  (HIS)

Neonatal cardiomyocyte isolation system  (NCIS)

Papain dissociation system  (PDS/PDS2)