Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.25 (chymopapain)
 430 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The inhibitory specificity of a protein from potato tubers that inhibits cysteine proteinases (potato cysteine proteinase inhibitor, PCPI) has been compared with that of chicken egg-white cystatin. Most proteinases that are inhibited by cystatin were also inhibited by PCPI, but the potato inhibitor inhibited stem bromelain and fruit bromelain, which are not inhibited by cystatin, and for which no protein inhibitor of comparable potency has previously been described. In contrast, papaya proteinase IV was unaffected by PCPI as it is by the cystatins, and the exopeptidase, dipeptidyl peptidase I, is inhibited by cystatins, but was unaffected by PCPI. The differences in inhibitory specificity between these proteins may well reflect differences between superfamilies of cysteine proteinase inhibitors.
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PMID:Inhibition of cysteine proteinases by a protein inhibitor from potato. 240 57

The complete amino acid sequence of the cysteine proteinase inhibitor from potato tubers was determined. The inhibitor is a single-chain protein having 180 amino acid residues. Its primary structure was elucidated by automatic degradation of the intact protein and sequence analysis of peptides generated by CNBr, trypsin and glycyl endopeptidase. A search through the protein sequence database showed homology to other plant proteinase inhibitors of different specificities and non-inhibitory proteins of M(r) around 20,000. On the basis of sequence homology, prediction of secondary structure and fold compatibility, based on a 3D-1D score to the three-dimensional profile of Erythrina caffra trypsin inhibitor, we suggest that the potato cysteine proteinase inhibitor belongs to the superfamily of proteins that have the same pattern of three-dimensional structure as soybean trypsin inhibitor. This superfamily would therefore include proteins that inhibit three different classes of proteinases-serine, cysteine and aspartic proteinases.
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PMID:The primary structure of inhibitor of cysteine proteinases from potato. 822 55

Cystatin CsC, a cysteine proteinase inhibitor from chestnut (Castanea sativa) seeds, has been purified and characterized. Its full-length cDNA clone was isolated from an immature chestnut cotyledon library. The inhibitor was expressed in Escherichia coli and purified from bacterial extracts. Identity of both seed and recombinant cystatin was confirmed by matrix-assisted laser desorption/ionization mass spectrometry analysis, two-dimensional electrophoresis and N-terminal sequencing. CsC has a molecular mass of 11,275 Da and pI of 6.9. Its amino acid sequence includes all three motifs that are thought to be essential for inhibitory activity, and shows significant identity to other phytocystatins, especially that of cowpea (70%). Recombinant CsC inhibited papain (Ki 29 nM), ficin (Ki 65 nM), chymopapain (Ki 366 nM), and cathepsin B (Ki 473 nM). By contrast with most cystatins, it was also effective towards trypsin (Ki 3489 nM). CsC is active against digestive proteinases from the insect Tribolium castaneum and the mite Dermatophagoides farinae, two important agricultural pests. Its effects on the cysteine proteinase activity of two closely related mite species revealed the high specificity of the chestnut cystatin.
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PMID:A chestnut seed cystatin differentially effective against cysteine proteinases from closely related pests. 986 28

A barley cDNA clone encoding a cysteine proteinase inhibitor was characterized. The deduced amino acid sequence of this barley cystatin (Hv-CPI) contains the motif QXVXG conserved among members of the cystatin superfamily. The gene (Icy), located on chromosome 2, was expressed in embryos, developing endosperms, leaves and roots as assessed by northern blot analysis. Western blot analysis detected a slightly retarded band in leaves that was not present in roots or seeds. In these two organs a more precise location of Hv-CPI was done by immuno-histochemical analysis, with polyclonal antibodies raised against the recombinant CPI protein expressed in Escherichia coli. This protein efficiently inhibited papain (Ki 2.0 x 10(-8) M) and ficin (Ki 2.2 x 10(-8) M) and, to a lesser extent, chymopapain (Ki 1.6 x 10(-7) M) and was inactive against bromelain. The Icy mRNA expression in vegetative tissues increased in response to anaerobiosis, dark and cold shock (6 degrees C).
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PMID:A constitutive cystatin-encoding gene from barley (Icy) responds differentially to abiotic stimuli. 1141 18

We examined the mechanism of action and compared the anthelmintic efficacy of cysteine proteinases from papaya, pineapple, fig, kiwi fruit and Egyptian milkweed in vitro using the rodent gastrointestinal nematode Heligmosomoides polygyrus. Within a 2 h incubation period, all the cysteine proteinases, with the exception of the kiwi fruit extract, caused marked damage to the cuticle of H. polygyrus adult male and female worms, reflected in the loss of surface cuticular layers. Efficacy was comparable for both sexes of worms, was dependent on the presence of cysteine and was completely inhibited by the cysteine proteinase inhibitor, E-64. LD50 values indicated that the purified proteinases were more efficacious than the proteinases in the crude latex, with purified ficin, papain, chymopapain, Egyptian milkweed latex extract and pineapple fruit extract containing fruit bromelain, having the most potent effect. The mechanism of action of these plant enzymes (i.e. an attack on the protective cuticle of the worm) suggests that resistance would be slow to develop in the field. The efficacy and mode of action make plant cysteine proteinases potential candidates for a novel class of anthelmintics urgently required for the treatment of humans and domestic livestock.
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PMID:Assessment of the anthelmintic effect of natural plant cysteine proteinases against the gastrointestinal nematode, Heligmosomoides polygyrus, in vitro. 1572 70