Affinity chromatography of cysteine peptidases.
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Aldehydes↗
Biomedical subjects
D J Buttle
Publications and source records attributed to D J Buttle.
Inhibition of cartilage proteoglycan release by a specific inactivator of cathepsin B and an inhibitor of matrix metalloproteinases. Evidence for two converging pathways of chondrocyte-mediated proteoglycan degradation.
OBJECTIVE: To investigate mechanisms of cartilage matrix destruction by a study of the effects of a specific inactivator of cathepsin B and an inhibitor of several matrix metalloproteinases (MMP) on cartilage proteoglycan release. METHODS: Cartilage explants were treated with either recombinant human interleukin-1 alpha (rHuIL-1 alpha) or retinoic acid in the presence or absence of the inhibitors, and proteoglycan release was quantitated. Tests for nonspecific effects of the inhibitors included reversibility, rates of protein synthesis and glycolysis, and effects on other rHuIL-1 alpha-mediated events. RESULTS: The cathepsin B inactivator inhibited rHuIL-1 alpha-stimulated proteoglycan release at nanomolar concentrations, but failed to significantly inhibit retinoic acid-stimulated proteoglycan release. An inhibitor of MMP was inhibitory to both rHuIL-1 alpha-stimulated release and retinoic acid-stimulated release. CONCLUSION: Cathepsin B is implicated in rHuIL-1 alpha-stimulated loss of cartilage proteoglycan. Its lack of involvement in retinoic acid-stimulated proteoglycan release suggests the existence of at least 2 pathways of cartilage proteoglycan breakdown, which may converge at the activation of a matrix prometalloproteinase.
Aggrecans↗
The two cysteine endopeptidases of legume seeds: purification and characterization by use of specific fluorometric assays.
Two endopeptidases are present in the seeds of Vigna aconitifolia (moth bean), and their activities increase during germination. One enzyme, which we term "vignain," can be assayed with benzyloxycarbonyl-phenylalanyl-arginyl-7-(4-methyl)coumarylamide as substrate. The second is legumain (EC 3.4.22.34), which can be assayed with benzyloxycarbonyl-alanyl-alanyl-asparaginyl-7-(4-methyl)-coumarylamide. The enzymes were purified, and their specificities for substrates and inhibitors were examined. Vignain has properties expected of a cysteine endopeptidase of the papain family, with the exception of a remarkably low reactivity with iodoacetate. Legumain is a very atypical cysteine endopeptidase, being insensitive to inhibition by chicken cystatin and E-64 (L-3-carboxy-2,3-trans-epoxypropionyl-leucyl-amido(4-guanidino )butane), and reacting more rapidly with iodoacetamide than with iodoacetate. We discuss our findings in relation to the literature on the proteolytic enzymes of legume seeds.
Amino Acid Sequence↗
The inhibition of interleukin 1-stimulated cartilage proteoglycan degradation by cysteine endopeptidase inactivators.
Cysteine endopeptidase inactivators were tested as inhibitors of interleukin 1-stimulated proteoglycan release from bovine nasal septum cartilage explants. Hydrophilic inactivators showed no inhibition at concentrations up to 100 microM. In contrast, lipophilic inactivators gave significant inhibition, which was both reversible and specific. No effects on interleukin 1 signal transduction were detected, but rates of proteoglycan synthesis were apparently increased. Our results suggest that one or more of the lysosomal cathepsins B, L and S mediate cytokine-stimulated proteoglycan degradation, and the turnover of newly synthesized proteoglycan, but that effective inhibitors must pass through membranes.
Animals↗
Lysosomal cysteine endopeptidases mediate interleukin 1-stimulated cartilage proteoglycan degradation.
The peptidyl diazomethane inactivator of cysteine endopeptidases, benzyloxycarbonyl-Tyr-Ala-CHN2, was tested as an inhibitor of interleukin 1 alpha-stimulated release of proteoglycan from bovine nasal septum cartilage explants. Like the previously tested epoxidyl peptide proinhibitor trans-epoxysuccinyl-leucylamido-(3-methyl)butane ethyl ester, it proved to be an effective inhibitor of proteoglycan release from cartilage, with significant inhibition at a concentration of 1 microM. The inhibition did not seem to be due to a general toxic effect. The rates of inactivation of the bovine cysteine endopeptidases by the peptidyl diazomethane, the epoxidyl peptide proinhibitor and its active form were determined. Benzyloxycarbonyl-Tyr-Ala-CHN2 proved to be a rapid inactivator of cathepsins L, S and B, but reacted much more slowly with cathepsin H and calpain. Thus it would appear that the latter two enzymes are not implicated in proteoglycan release in our test system. The peptidyl diazomethane and epoxidyl peptide proinhibitor (above) were also tested for their effects on three other interleukin 1-mediated cellular events, namely epidermal growth factor receptor transmodulation, and interleukin 6 and prostaglandin E2 production. In all cases the inactivators did not interfere with the response to interleukin 1 in human gingival fibroblasts. We conclude that one or more of the lysosomal cysteine endopeptidases cathepsins B, L and S mediate interleukin 1-stimulated cartilage proteoglycan degradation without affecting signal transduction.
Animals↗
Inhibition of interleukin 1-stimulated cartilage proteoglycan degradation by a lipophilic inactivator of cysteine endopeptidases.
Inactivators of cysteine endopeptidases were tested as inhibitors of the cytokine-stimulated release of proteoglycan from cartilage. The test system consisted of bovine nasal septum cartilage maintained in organ culture, and the stimulus was provided by recombinant human interleukin 1 alpha. L-3-Carboxy-2,3-trans-epoxypropionyl-leucylamido-(4-guanidin o)butane (E64) and L-3-carboxy-2,3-trans-epoxypropionyl-leucylamido-(3-methyl)b utane (Ep475) showed no inhibition at concentrations up to 100 microM. In contrast, trans-epoxysuccinyl-leucylamido-(3-methyl)butane ethyl ester (Ep453), a 'prodrug' of Ep475, was an effective inhibitor. The LL-, LD- and DL-isomers gave significant inhibition at 10 microM, and the DD-isomer was inhibitory at 100 microM. None of the isomers had any detectable effect on protein synthesis or glycolysis, and their inhibitory effects were reversible. Iodoacetate inhibited proteoglycan release by a general toxic effect. Our results suggest that cysteine endopeptidase(s) play a part in cytokine-stimulated cartilage breakdown, but that effective inhibitors must pass through membranes.
Animals↗
CA074 methyl ester: a proinhibitor for intracellular cathepsin B.
The specificity of compound CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L-isoleucyl-L-pro line] for the inactivation of cathepsin B was quantified in in vitro measurements with cysteine endopeptidases from cattle, it being found that the compound is a very rapid inactivator of cathepsin B (rate constant 112,000 M-1.s-1), with barely detectable action on cathepsins H, L, and S or m-calpain. Conversion of the proline carboxyl group of the inhibitor to the methyl ester virtually abolished the effect on cathepsin B, and a possible explanation for the importance of the carboxyl is presented on the basis of the tertiary structure of cathepsin B. It was found that CA074 methyl ester (1 microM, 3 h) caused selective inactivation of the intracellular cathepsin B of human gingival fibroblasts in culture, in contrast to other available agents, and we suggest that CA074 methyl ester will be of value in the elucidation of the biological functions of cathepsin B.
Binding Sites↗
Low-dose, low-volume chemonucleolysis. A biochemical study.
Thirty patients with persistent sciatica due to a single disc protrusion were injected with 0.5 ml (2.0 mg) or 2.0 ml (8.0 mg) of chymopapain. Serial 24-hour urine samples were collected 1 day preinjection and for 5 days postinjection for glycosaminoglycan analysis. There was a significant increase in urinary glycosaminoglycan in both groups following chemonucleolysis, but no significant difference was found between the two groups in the total excretion of glycosaminoglycan during the 5-day period. Low-dose, low-volume chemonucleolysis may be as effective as standard doses in releasing glycosaminoglycan from intervertebral discs.
Adult↗
The baculovirus Autographa californica nuclear polyhedrosis virus genome includes a papain-like sequence.
The published DNA sequence that includes the gene for the envelope glycoprotein gp67 of the baculovirus Autographa californica nuclear polyhedrosis virus also contains a segment that shows 32% amino acid identity to papain, a cysteine endopeptidase from the papaya plant (Carica papaya). The viral papain-like sequence is apparently affected by a frame-shift mutation, but otherwise appears capable of encoding a functional enzyme. Catalytically essential amino acids appear to be conserved, as do disulphide bridges. The overall structure of the putative protein is similar to that of papain, as judged by hydropathy profile. Secondary structure prediction using a consensus of seven methods indicates that the putative viral enzyme retains the alpha/beta domain structure of papain, including the long helix beginning with cysteine-25. Infecting SF9 cells with the virus did not lead to a detected increase in cysteine endopeptidase activity, and a cysteine endopeptidase inactivator appeared to have no effect on infectivity. Irrespective of whether the sequence encodes a functionally active cysteine endopeptidase, this is the first example of a papain-related sequence in a viral genome.
Amino Acid Sequence↗
Clostripain: characterization of the active site.
In view of the probability that clostripain (EC 3.4.22.8) is fundamentally different in structure from other known cysteine endopeptidases, it was of interest to examine the characteristics of the active site. Z-Phe-Lys-CH2S(CH3)2 irreversibly and rapidly inactivated clostripain, and leupeptin was found to be the most potent reversible inhibitor yet reported for the enzyme. Clostripain was inhibited weakly by some protein inhibitors of serine endopeptidases, and required Ca2+ for stability and activity. Mg2+ and Sr2+ were ineffective. Rapid inactivation by diethylpyrocarbonate, reversed by hydroxylamine, indicated that histidine is essential for catalytic activity. Clostripain was more rapidly inactivated by iodoacetamide than by iodoacetate, with unique pH-dependences of reaction.
Amino Acid Sequence↗
Human sputum cathepsin B degrades proteoglycan, is inhibited by alpha 2-macroglobulin and is modulated by neutrophil elastase cleavage of cathepsin B precursor and cystatin C.
The high-Mr alkali-stable form of cathepsin B was purified from purulent human sputum. It was shown to solubilize proteoglycan monomer entrapped in polyacrylamide at a rate comparable with that of human lysosomal cathepsin B. Like the enzyme from lysosomes, sputum cathepsin B was bound by human alpha 2-macroglobulin, which inhibited its action on proteoglycan. Cystatin C in purulent sputum was shown to be the N-terminally truncated form generated by neutrophil elastase cleavage, and sputum cathepsin B was only weakly inhibited by recombinant cystatin C that had been cleaved by neutrophil elastase in vitro. Addition of neutrophil elastase to mucoid sputum led to a 5-fold increase in cathepsin B activity concomitant with a lowering in Mr of the cysteine proteinase from 40,000 to 37,000, i.e. the size of the active enzyme purified from purulent sputum. It is concluded that the high-Mr form of cathepsin B present in purulent sputum is a functional proteinase, unlike similar forms of the enzyme secreted by mammary gland in organ culture. The activity of cathepsin B in sputum is modulated by neutrophil elastase, by a combination of inhibitor inactivation and zymogen activation.
Amino Acid Sequence↗
Human cystatin C. role of the N-terminal segment in the inhibition of human cysteine proteinases and in its inactivation by leucocyte elastase.
Leucocyte elastase in catalytic amounts was observed to rapidly cleave the Val-10-Gly-11 bond of the human cysteine-proteinase inhibitor cystatin C at neutral pH. The resulting modified inhibitor had size and amino acid composition consistent with a cystatin C molecule devoid of the N-terminal Ser-1-Val-10 decapeptide. Leucocyte-elastase-modified cystatin C had more than 240-fold lower affinity than native cystatin C for papain. Removal of the N-terminal decapeptide of human cystatin C also decreased inhibition of human cathepsins B and L by three orders of magnitude, but decreased inhibition of cathepsin H by only 5-fold. A tripeptidyldiazomethane analogue of of the N-terminal portion of cystatin C was a good inhibitor of cathepsins B and L but a poor inhibitor of cathepsin H. It therefore appears that amino acid side chains of the N-terminal segment of cystatin C bind in the substrate-binding pockets of cathepsins B and L but not in those of cathepsin H. It is argued that the N-terminal cystatin C interaction with cathepsin B is physiologically important and hence that leucocyte elastase could have a function as a regulator of extracellular cysteine-proteinase inhibitory activity at sites of inflammation.
Amino Acid Sequence↗
Regulation of cystatin C activity by serine proteinases.
The effect of four human serine proteinases on the human cysteine proteinase inhibitor, cystatin C, has been studied in vitro. Neutrophil elastase in catalytic amounts was observed to rapidly cleave cystatin C at neutral pH, thereby giving rise to a modified form of the inhibitor lacking the N-terminal Ser1-Val10 decapeptide. The two other leukocyte serine proteinases, cathepsin G and neutrophil proteinase 4, did not catalytically hydrolyse cystatin C bonds. Neither had the seminal plasma serine proteinase, prostate-specific antigen, any effect on cystatin C. The physiological implications of neutrophil elastase catalysed modification of cystatin C are discussed, and recent findings indicating that this reaction also occurs in vivo are reviewed.
Amino Acid Sequence↗
Inhibition of cysteine proteinases by a protein inhibitor from potato.
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.
Cystatins↗
The amino acid sequence of a novel inhibitor of cathepsin D from potato.
The amino acid sequence of a cathepsin D inhibitor isolated from potato is described. It was determined by analysis of peptides generated by use of the glycine-specific proteinase PPIV. The order of the peptides was established by examination of tryptic peptides derived from the two cyanogen bromide peptides. The inhibitor comprises 187 amino acid residues, and has a calculated Mr of 20,450.
Amino Acid Sequence↗
The cysteine proteinases of the pineapple plant.
The pineapple plant (Ananas comosus) was shown to contain at least four distinct cysteine proteinases, which were purified by a procedure involving active-site-directed affinity chromatography. The major proteinase present in extracts of plant stem was stem bromelain, whilst fruit bromelain was the major proteinase in the fruit. Two additional cysteine proteinases were detected only in the stem: these were ananain and a previously undescribed enzyme that we have called comosain. Stem bromelain, fruit bromelain and ananain were shown to be immunologically distinct. Enzymic characterization revealed differences in both substrate-specificities and inhibition profiles. A study of the cysteine proteinase derived from the related bromeliad Bromelia pinguin (pinguinain) indicated that in many respects it was similar to fruit bromelain, although it was found to be immunologically distinct.
Amino Acid Sequence↗
Interactions of papaya proteinase IV with inhibitors.
Papaya proteinase IV (PPIV) is not inhibited by chicken cystatin, or human cystatins A or C, unlike most other proteinases of the papain superfamily. The enzyme inactivates chicken cystatin and human cystatin C by limited proteolysis of the glycyl bond previously shown to be involved in the inhibitory inactivity of the cystatins, but has no action on cystatin A. Contamination of commercial crystalline papain with PPIV accounts for the limited proteolysis of cystatins by 'papain' reported previously. PPIV is slowly bound by human alpha 2-macroglobulin. The enzyme is irreversibly inactivated by E-64, and by peptidyl diazomethanes containing glycine in P1 and a hydrophobic side-chain in P2. The reaction of PPIV with iodoacetate is extremely slow. PPIV is inhibited by peptide aldehydes despite the presence of bulky sidechains in P1, suggesting that these reversible inhibitors do not bind as substrate analogues.
Binding Sites↗
Selective cleavage of glycyl bonds by papaya proteinase IV.
The specificity of papaya proteinase IV (PPIV) has been examined with small substrates and a protein. With both classes of substrate, the enzyme shows a marked selectivity for cleaving glycyl bonds. Boc-Ala-Ala-Gly-NHPhNO2 is a convenient substrate for routine assays that discriminate well against chymopapain, the most common contaminant of PPIV. Sixteen cleavage points in beta-trypsin were identified, of which 13 are glycyl bonds. Tentative suggestions are made as to the reasons for lack of cleavage of some other glycyl bonds. The structure of PPIV has been modelled on that of papain, and we suggest that the replacement of the highly conserved residues Gly-65 and Gly-23 by arginine and glutamic acid, respectively, can account for the specificity of PPIV.
Amino Acid Sequence↗