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)

The three proteinases present in papaya latex: papain (EC 3.4.22.2) chymopapain and papaya proteinase III (EC 3.4.22.6), were standardized by active-site titration, and compared in proteolytic activity against azocasein, serum albumin and cartilage proteoglycan. The activities were all of the same order, although there were differences in pH dependence. SDS-polyacrylamide gel electrophoresis of the early products of digestion of albumin and phosphorylase a showed very similar patterns for the three papaya proteinases. Kinetic parameters for hydrolysis of benzyloxycarbonyl-phenylalanyl-arginyl-7(4-methyl)coumarylamide were determined for the three enzymes. Values for kcat/Km varied only within a factor of 2, but the individual constants were much higher for papain than for chymopapain and papaya proteinase III. In contrast to the results obtained with the synthetic substrate, the kinetic parameters for the initial hydrolysis of succinyl-albumin were very similar for the three papaya proteinases. This was consistent with their similar proteolytic activities in other assays.
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PMID:The proteolytic activities of chymopapain, papain, and papaya proteinase III. 391 69

An extracellular cysteine protease inhibitor (ECPI-2) was purified to homogeneity from the culture filtrate of Chlorella sp. 4533 by the combination of various column chromatographies. The molecular mass of the inhibitor was estimated to be 340 kDa by SDS-PAGE. The inhibitor was extremely heat-stable under acidic or neutral condition. ECPI-2 exhibited an inhibitory activity against the proteolytic activity of papain, ficin, or chymopapain, but not against stem bromelain or cathepsin B. The inhibitor showed no inhibitory activity against trypsin, alpha-chymotrypsin or thermolysin. ECPI-2 contains 33.6% carbohydrate residues by weight and inhibits papain at a molar ratio of 1:2. The proteolysis of the inhibitor by trypsin or alpha-chymotrypsin was apparent, but the inhibitory activity of ECPI-2 was unaffected by these enzymes. The alpha-chymotrypsin hydrolysis product from ECPI-2 was further separated into six fractions by gel filtration. From these results, it is suggested that ECPI-2 has several reactive sites for papain.
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PMID:Purification and characterization of extracellular cysteine protease inhibitor, ECPI-2, from Chlorella sp. 1656 14