Chymopapain, specificity

CoUagenase specifically cataly2es the hydrolysis of coUagen, and is used in debridement of dermal ulcers and bums (191). It, like chymopapain, is also useful in the treatment of herniated lumbar disks (192,193). The rationale for coUagenase treatment in this instance is based on the preponderance of coUagen in herniated disk tissue, and the inabiUty of other en2ymes to dissolve coUagen (194). 

Jacquct et al. described the proteolytic specificities of chymopapain and papaya proteinase Q [36]. The polypeptide chain of caricain contains 216 amino acid residues (Mr 23283). The molecule shares 148 identical amino acid residues (68,5ft) with papain. 141 with chymopapain (65,2ft), and 175 with glycyl endopeptidase (81.0ft). The Ms,lllOnin is 1U [20]. The three-dimensional structure of caricain has been determined by x-ray diffraction analysis [37,38]-... 

The residues in the Sj subsite that make the most intimate contact are those of Val-133, Val-157, Ala-160, Pro-68, and iyr-67. In the four enzymes of the papaya latex, ail incite groups remain hydrophobic, wiui the exception of Pro-68, which is replaced by Olu in chymopapain and in gtycyl endopeptidase. The nonpolar character, and generally specificity, of the S2 subsite would therefore be conserved. 

To date, the latex of Carica papaya L. is known to contain at least four different proteolytic enzymes, namely, papain (E.C. 3.4.22.2), chymopapain (E.C. 3.4.22.6), caricain or papaya proteinase III or 2 (E.C. 3.4.22.30), and glycyl endopeptidase or papaya proteinase IV (E.C. 3.4.22.25). The importance of the latex of the unripe fruit of the tropical tree Carica papaya L. was first noted by G. C. Roy, who in 1873 published in the Calcutta Medical Journal (see Ref. 1) an article entitled The solvent action of papaya juice on the nitrogenous articles of food. The name papain was used for the first time by Wurtz and Bouchet [2] to describe partially purified cysteine proteinases from the papaya latex. They wrote, nous designerons ce ferment sous le nom de papa ine." In 1880, Wurtz postulated that papain acts in fibrin digestion by becoming bound to the fibrin [3]. This is remarkable in that Emil Fisher first described the specific association of enzyme with substrate in 1898. Since that time, many names have been used for commercial latex products, e.g., papayotin, papaoid, etc. 

In 1988, Looze et al. published a series of articles on the cysteine proteinases from papaya latex. In the first article, they described an alternative way to purify chymopapain and papaya proteinase Q to homogeneity [32], In the following articles the primary structures of chymopapain [33] and papaya proteinase 12 [34] were described (Fig. 1). The primary structure of chymopapain determined by Watson et al. [35] is in perfect agreement with the results of Dubois et al. Jacquet et al. described the proteolytic specificities of chymopapain and papaya proteinase 12 [36]. The polypeptide chain of caricain contains 216 amino acid residues (Mr 23283). The molecule shares 148 identical amino acid residues (68.5%) with papain, 141 with chymopapain (65.2%), and 175 with glycyl endo-peptidase (81.0%). The Ai%,280nm is 18.3 [20]. The three-dimensional structure of caricain has been determined by x-ray diffraction analysis [37,38]. 

A. Jacquet, T. Kleinschmidt, T. Dubois, A. G. Schnek, Y. Looze, and G. Braunitzer. The thiol proteinases from the latex of Carica papaya L. IV. Proteolytic specificities of chymopapain and papaya proteinase omega determined by digestion of alpha-globin chains. Biol. Chem. Hoppe-Seyler 370 819 (1989). 

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