Papain papaya proteinase

This enzyme [EC 3.4.22.6], also known as papaya proteinase II, is a member of the peptidase family Cl. It is the major endopeptidase of papaya (Carica papaya) latex. It has a specificity similar to that of papain. In addition, there are a number of chromatographic forms of the enzyme. 

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]-... 

Affinity purification of the novel cysteine proteinase papaya proteinase IV and papain fiom papaya latex. Biochan. J. 261 469 (1989). 

Carica papaya (papaya, paw-paw) (Caricaceae) [recombinant] Carica papain pro-region (107 aa 12 kDa) Caricain [8 nM], Chymopapain [12 nM], Papain [2 nM], Papaya proteinase IV [31 [152]... 

Papain [2nM], chymopapain [12nM], caricain [8nM], papaya proteinase IV [3]... 

Papain Neutral Proteinase Carica papaya Meat and Plant Protein Hydrolysis Yields Amino... 

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]. 

Specificity is often described in terms of the subsite model of Schechter and Berger [67,68] (Fig. 6). In terms of this model, the substrate may be represented as P4-P3-P2-Pi-T-P i-P,2, where P represents an amino acid residue that binds to a particular region in the active center (subsite Si.S i, etc.) and the arrow indicates the scissible bond, of which Pi provides the carbonyl moiety and P i the amino moiety. The reactivity and inhibition studies of Berger and Schechter [68] showed that papain has a strong affinity for Phe, Tyr, Val, or Leu at P2 of the substrate. A similar preference is shown by all papaya proteinases, although significant differences exist. 

D. J. Buttle, A. A. Kembhavi, S. Sharp, R. E. Shute, D. H. Rich, and A. J. Barrett. Affinity purification of the novel cysteine proteinase papaya proteinase IV and papain from papaya latex. Biochem. J. 267 469 (1989). 

El is well known that the cysteine proteinase of the papaya latex differ in their ability to hydrolyze proteins and synthetic peptides. Schechter and Beiger [67] first demonstrated that the landing regions in the active center of proteinases can be divided into different subtitles, of whidi die Sz subsite seems to be the most important in papain. 

A, K. Balls and R Linewcaver, Isolation and properties of crystalline papain. J. BioL E. F.lamen and A. K. Balk. Chymopapain a new crystalline proteinase from papaya... 

Not only defense secondary metabolites but also defense proteins may exist as precursors. For example, papain, a cysteine proteinase that exists in papaya latex and recently found to have strong defense activity, is kept in laticifer as an inactive precursor and within 2 min after wounding, it becomes active.1 4... 

In 1937, Balls et al. [4] purified one of the proteolytic fractions and called their crystalline enzyme papain. This was an unfortunate choice, since the name papain is also used for the crude papaya latex containing multiple enzymes. In 1939, Lineweaver and Balls published a refinement of the isolation method, and they also reported the presence in the papaya latex of another proteinase with a higher ratio of milk-clotting to hemoglobin-digesting activity than papain [5], In 1941 Jansen and Balls presented a description of a second proteolytic enzyme [6]... 

B. S. Baines and K. Brocklehurst. Isolation and characterization of the four major cysteine-proteinase components of the latex of Carica papaya L. Reactivity characteristics towards 2,2 -dipyridyl disulfide of the thiol groups of papain, chymopapains A and B, and papaya peptidase A. J. Protein Chem. 7 119 (1982). 

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