7016. Papain

Nomenclature

CAS number: 9001-73-4
Papayotin; vegetable pepsin; Arbuz; Nematolyt; Summetrin; Tromasin; Velardon (Organon); Vermizym.

Description and references

First recognized member of the class of proteolytic enzymes that needs a free sulfhydryl group for activity. Isolated from the latex of the green fruit and leaves of Carica papaya L., Caricaceae. Initial isolation and crystallization: Balls et al., Science 86, 379 (1937); Balls, Lineweaver, J. Biol. Chem. 130, 669 (1939). Prepn from commercial dried papaya latex and physical properties: Kimmel, Smith, ibid. 207, 515 (1954); see also ibid. 533-573; Becker, Econ. Bot. 12, 62 (1958). Purification: Gibian, Bratfisch, US 2950227 (1960 to Schering AG); Lesuk, US 3011952 (1961 to Sterling Drug); Blumberg et al., Eur. J. Biochem. 15, 97 (1970). The papain molecule consists of one folded polypeptide chain of 212 residues, mol wt ≈23,400. Complete amino acid sequence: Drenth et al., Nature 218, 929 (1968); Mitchel et al., J. Biol. Chem. 245, 3485 (1970). Mechanism of action studies: Morihara, J. Biochem. 62, 250 (1967). Use in treatment of contact lenses to prolong wearing time in keratoconic patients with papillary conjunctivitis: D. R. Korb et al., Arch. Ophthalmol. 101, 48 (1983). Reviews: Kimmel, Smith in Adv. Enzymol. Relat. Subj. Biochem. 19, 267-334 (1957); Glazer, Smith in The Enzymes vol. III, P. D. Boyer, Ed. (Academic Press, New York, 3rd ed., 1971) pp 501-537; see also Drenth et al., ibid. 485-498 and eidem, Adv. Protein Chem. 25, 79-115 (1971) for a comprehensive review of the structural elucidation.

Properties

White or grayish-white, slightly hygroscopic powder. uv max: 278 nm (A1%1cm 25.0). Incompletely sol in water, glycerol. Practically insol in most organic solvents. Keep well closed. Potency varies according to process of prepn, etc. with the usual grade digesting ≈35 times its wt of lean meat. Best grades render sol 200-300 times their wt of coagulated egg albumin in alkaline media. A temp. range of 60-90° is favorable for the digestive process with 65° the optimum point. Best pH is 5.0, but it functions also in neutral or alkaline media. Activated by reduction (HCN, H2S etc.) and inactivated by oxidation (H2O2, iodoacetate).

Note

The term papain is currently applied to both the crude dried latex and the crystalline proteolytic enzyme.

Use

For tenderizing meats; for clearing beverages; for bating skins.

Therapeutic Category

Enzyme (proteolytic). Debriding agent; digestive aid. Has been used to prevent adhesions; as anthelmintic (Nematodes).

Keywords

Anthelmintic (Nematodes); Debriding Agent; Digestive Aid; Enzyme; Proteolytic