Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.6 (chymopapain)
 407 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two proteases, one of which is papaya peptidase A and the other a previously unknown enzyme in papaya latex have been purified to homogeneity in a simple two stage process. Both are markedly less reactive than papain or chymopapain. Each has a molecular weight of 24,000, N-terminal sequences commencing Leu-Pro-Glu, and contains no carbohydrate. Their amino acid compositions differ for several residues. The essential -SH groups of the enzymes examined appear to be 'masked' in the native state.
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PMID:A purification and some properties of two proteases from papaya latex. 47 25

The proteolytic specificities of chymopapain and papaya proteinase omega were investigated by using the alpha-chains of manatee and mole haemoglobin, whose primary structures are known, as substrates. The resulting peptides from each enzymatic cleavage were isolated by gel filtration on Sephadex G-25, followed by reversed-phase HPLC of the separated peaks and, in some cases, further purified by preparative thin-layer electrophoresis. The purified peptides were then identified on the basis of their amino-acid composition. The proteolytic specificities of chymopapain and papaya proteinase omega, deduced from the experimental cleavage patterns, are compared to that of papain. As in the case of papain, the specificity-determining factor is the amino-acid residue of the substrate that will be bound in subsite S2 (the next but one from the scissible bond). Aromatic residues in this position, preferred by papain, are not important for chymopapain and papaya proteinase omega. Cleavages preferentially occur when S2 is occupied by leucine, valine or threonine. For chymopapain, proline in position S2 also causes cleavage.
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PMID: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. 268

Proteases regulate numerous biological processes with a degree of specificity often dictated by the amino acid sequence of the substrate cleavage site. To map protease/substrate interactions, a 722-member library of fluorogenic protease substrates of the general format Ac-Ala-X-X-(Arg/Lys)-coumarin was synthesized (X=all natural amino acids except cysteine) and microarrayed with fluorescent calibration standards in glycerol nanodroplets on glass slides. Specificities of 13 serine proteases (activated protein C, plasma kallikrein, factor VIIa, factor IXabeta, factor XIa and factor alpha XIIa, activated complement C1s, C1r, and D, tryptase, trypsin, subtilisin Carlsberg, and cathepsin G) and 11 papain-like cysteine proteases (cathepsin B, H, K, L, S, and V, rhodesain, papain, chymopapain, ficin, and stem bromelain) were obtained from 103,968 separate microarray fluorogenic reactions (722 substrates x 24 different proteases x 6 replicates). This is the first comprehensive study to report the substrate specificity of rhodesain, a papain-like cysteine protease expressed by Trypanasoma brucei rhodesiense, a parasitic protozoa responsible for causing sleeping sickness. Rhodesain displayed a strong P2 preference for Leu, Val, Phe, and Tyr in both the P1=Lys and Arg libraries. Solution-phase microarrays facilitate protease/substrate specificity profiling in a rapid manner with minimal peptide library or enzyme usage.
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PMID:High throughput substrate specificity profiling of serine and cysteine proteases using solution-phase fluorogenic peptide microarrays. 1570 70