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D J Buttle

Publications and source records attributed to D J Buttle.

At least 73 records · Page 4Linked to original sources
PubMed1990

Debridement of experimental full-thickness skin burns of rats with enzyme fractions derived from pineapple stem.

A limited in vivo study using 12 rats with full-thickness skin burns injuries was carried out. The animals were treated 24 h postburn with two newly discovered enzyme fractions derived from the stem of the pineapple (Ananas comosus). The results indicated that even debridement of the injury could be effected rapidly (within 4 h). Although the details of enzyme formulation and clinical application have yet to be established, these findings clearly suggest that two enzyme fractions from pineapple stem have potential as non-surgical debriding agents.

Animals↗
PubMed1990

Levels of neutrophil elastase and cathepsin B activities, and cystatins in human sputum: relationship to inflammation.

Sputum samples from 25 patients with bronchiectasis were assayed enzymatically for myeloperoxidase, neutrophil elastase and cathepsin B, and immunologically for cystatin A, cystatin B, cystatin C, cystatin S and kininogen. High myeloperoxidase and neutrophil elastase levels were found in those sputum samples that were assessed visually to be purulent. These samples were also found to contain high levels of cathepsin B activity and cystatin A, but low levels of cystatin S and of the most effective cathepsin B inhibitor, cystatin C. In contrast, sputum samples that were low in myeloperoxidase and neutrophil elastase activities had low levels of cathepsin B and cystatin A, but high cystatin C and S levels. It is concluded that cathepsin B activity in sputum is positively correlated with the degree of inflammation and neutrophil recruitment. Although this may be due in part to reduced amounts of cathepsin B inhibitors, particularly cystatin C, theoretical considerations suggest that factors other than the gross level of inhibitors must be involved in the control of cathepsin B activity.

Bronchiectasis↗
PubMed1990

The preparation of fully active chymopapain free of contaminating proteinases.

Chymopapain (EC 3.4.22.6) was purified from commercially available dried latex of papaya (Carica papaya) by extraction at acidic pH, cation-exchange chromatography and active site-directed affinity chromatography on immobilized alanyl-phenyl-alaninaldehyde semicarbazone, with elution by mercuric chloride. The product was found by immunoassay to be essentially free of the other cysteine proteinases from papaya, including papaya proteinase IV, and was fully active. The rate of alkylation of the active site cysteine of chymopapain by iodoacetate was found to be sufficiently rapid and selective for this reagent to be used as an active-site titrant.

Binding Sites↗
PubMed1989

Papaya proteinase IV amino acid sequence.

The amino acid sequence of papaya proteinase IV (PPIV), a major proteinase from the latex of Carica papaya [(1989) Biochem. J. 261, 469-476] is described. The enzyme has a high degree of sequence identity with papaya proteinase III, chymopapain and papain (81, 70 and 67%, respectively), and is clearly a member of the papain superfamily of cysteine proteinases. Nevertheless, the sequence shows substitution of certain residues conserved in all other known members of the superfamily. It is suggested that some of these substitutions may account for the unusual specificity of PPIV.

Amino Acid Sequence↗
PubMed1989

Affinity purification of the novel cysteine proteinase papaya proteinase IV, and papain from papaya latex.

A procedure is described for the purification of a previously undetected cysteine proteinase, which we have called papaya proteinase IV, from spray-dried latex of the papaya (Carica papaya) plant. The purification involves affinity chromatography on Gly-Phe-aminoacetonitrile linked to CH-Sepharose 4B, with elution by 2-hydroxyethyl disulphide at pH 4.5. The product thus obtained is a mixture of almost fully active papain and papay proteinase IV, which are then separated by cation-exchange chromatography. A preliminary characterization of papaya proteinase IV showed it to be very similar to chymopapain in both molecular size and charge. However, the new enzyme is immunologically distinct from the previously characterized cysteine proteinases of papaya latex. It also differs in its lack of activity against the synthetic substrates of the other papaya proteinases, in its narrow specificity against protein substrates and its lack of inhibition by chicken cystatin. Papaya proteinase IV is abundant, contributing almost 30% of the protein in spray-dried papaya latex, and contamination of chymopapain preparations with this enzyme may account for some of the previously reported heterogeneity of chymopapain.

Catalysis↗
PubMed1989

Stem bromelain: amino acid sequence and implications for weak binding of cystatin.

The amino acid sequence of stem bromelain, the major cysteine proteinase from pineapple stem is described. It shows that the enzyme is a member of the papain superfamily of cysteine proteinases, but is not very closely related to any other known member of this group. The sequence shows mutation or deletion of several residues that have been conserved in cysteine proteinases examined previously, including Asn-175 (papain). We suggest that some of these changes have the effect of altering the active-site geometry of stem bromelain, and that this accounts for the resistance of the enzyme to inhibition by cystatins and E-64[L-3-carboxy-2,3-trans-epoxypropionylleucylamido(4-guanidino)b utane].

Amino Acid Sequence↗
PubMed1989

Physiological variables affecting collagen lattice contraction by human dermal fibroblasts.

Normal human dermal fibroblasts cultured in collagen lattices can compact that matrix by the process known as lattice contraction. That process is a model of the pathological one of scar contracture or wound contraction and is affected by several factors. Lattice contraction is promoted by the addition of adequate amounts of fetal bovine serum to the medium (maximum contraction with 10% serum). The process requires energy, of which glucose and pyruvate have been shown to be adequate sources. When glucose is used as the substrate, the major pathway of energy generation appears to be anaerobic metabolism. When pyruvate is the only substrate, aerobic metabolism may be crucial. The synthesis of DNA is not required for lattice contraction, while protein synthesis is, although the identities of the specific proteins are unknown. Impairment of calcium ion transport inhibits lattice contraction, and the specific inhibition of calmodulin-calcium interactions by W-7 blocks contraction. W-7 at a concentration of 6 x 10(-6) M blocks lattice contraction completely, while it has no effect at any lower concentration. Impairing dynamic microtubule activity impairs contraction. Disrupting microfilaments by cytochalasin B completely blocks lattice contraction. Microfilament function and calcium-calmodulin may be linked by a mechanism involving myosin-ATPase. The process of cell-mediated lattice contraction requires the production of energy, protein synthesis, and a functional cytoskeleton.

Calcium↗
PubMed1988

Ananain: a novel cysteine proteinase found in pineapple stem.

A previously unknown cysteine proteinase, named ananain, has been isolated from crude commercial pineapple stem bromelain. The purification procedure involved affinity chromatography on Sepharose-Gly-Phe-glycinaldehyde semicarbazone, and cation-exchange chromatography. The relative molecular mass of ananain was very similar to that of bromelain (25,000 and 26,000, respectively), but ananain differed greatly in specificity for hydrolysis of peptide and protein substrates. The new enzyme behaved as a typical cysteine proteinase in showing strong inhibition by chicken cystatin, whereas bromelain was scarcely affected. Ananain was also shown to be immunologically distinct from bromelain. The significance of the discovery of ananain for the interpretation of previous work on "bromelain" is pointed out.

Binding Sites↗
PubMed1988

A catalytically active high-Mr form of human cathepsin B from sputum.

A cysteine proteinase from purulent sputum was partially purified by a method involving affinity chromatography on Sepharose-aminohexanoylphenylalanylglycinaldehyde semicarbazone. It was immunologically related to lysosomal cathepsin B from human liver and was similar in many, but not all, other aspects. It was catalytically active, as demonstrated by active-site-directed radioiodination, and hydrolysed three cathepsin B substrates, two with Km values similar to those of lysosomal cathepsin B. In addition, the rates of inactivation of the sputum and lysosomal forms of the enzyme by L-3-carboxy-2,3-transepoxypropionyl-leucylamido(4-guanidino) butane (Compound E-64) were very similar. However, the sputum enzyme differed from lysosomal cathepsin B in the following respects. Inhibition by chicken cystatin was much weaker for sputum cathepsin B than for the lysosomal enzyme. Sputum cathepsin B had greater stability at pH 7.5 and a higher apparent Mr, even after deglycosylation, than lysosomal cathepsin B. We conclude that the form of cathepsin B found in sputum is probably a truncated form of human procathepsin B, with some differences in properties that could be of physiological importance.

Binding Sites↗
PubMed1988

Evidence for lipid-associated serine proteases and metalloproteases in human bronchoalveolar lavage fluid.

1. We have investigated the nature of elastase activity in bronchoalveolar lavage samples from healthy cigarette smokers and subjects with emphysema. 2. Initial experiments with pure human leucocyte elastase showed this enzyme to be inhibited by high concentrations (greater than 10 mmol/l) of ethylenediaminetetra-acetate, indicating that results of previous studies of 'metalloelastase' activity in bronchoalveolar lavage were ambiguous. 3. We have nevertheless demonstrated the presence in bronchoalveolar lavage of an elastase with the characteristics of a metalloproteinase, although samples also contained a substantial amount of activity that was sensitive to serine proteinase inhibitors. 4. Fractionation of lavage fluid supernatant by size-exclusion chromatography demonstrated most of the elastase activity to be of molecular mass greater than 300 kDa. Treatment of samples with lipase or detergent caused a reduction in metalloelastase activity and the generation of lower-molecular-mass components (90-100 kDa and 40 kDa) which were predominantly serine elastases. This suggested that the enzymes were associated with lipid.

Adult↗
PubMed1988

Quantitative assessment of human proteinases as agents for chemonucleolysis.

A rabbit model system is described. It allows accurate measurement of the dose-dependent loss of glycosaminoglycan from the nucleus pulposus of lumbar intervertebral discs after injection of a proteinase. At the dose equivalent to that of chymopapain used in human chemonucleolysis, two human serine proteinases, cathepsin G and chymotrypsin, were as effective as chymopapain in removing up to 80% of the glycosaminoglycan from the disc. A cysteine proteinase, cathepsin B released no more than 45% of glycosaminoglycan. X-ray films clearly showed narrowing of the disc space when 30-40% of glycosaminoglycan was removed. The degradation of the nucleus pulposus was seen histologically as loss of toluidine blue metachromasia.

Animals↗
PubMed1986

Improved quantitation and discrimination of sulphated glycosaminoglycans by use of dimethylmethylene blue.

The dimethylmethylene blue assay for sulphated glycosaminoglycans has found wide acceptance as a quick and simple method of measuring the sulphated glycosaminoglycan content of tissues and fluids. The available assay methods have lacked specificity for sulphated glycosaminoglycans in the presence of other polyanions, however, and have not discriminated between the different sulphated glycosaminoglycans. We now describe a modified form of the dimethylmethylene blue assay that has improved specificity for sulphated glycosaminoglycans, and we show that in conjunction with specific polysaccharidases, the dimethylmethylene blue assay can be used to quantitate individual sulphated glycosaminoglycans.

Chondroitin Lyases↗
PubMed1986

The biochemistry of the action of chymopapain in relief of sciatica.

A study has been made of the mechanism of action of intradiscal injections of preparations of chymopapain in the treatment of sciatica. Such preparations were found to contain at least four distinct proteins, but enzymatically active chymopapain was the component mainly responsible for releasing glycosaminoglycan from cartilaginous tissue. Previous suggestions that an electrostatic interaction between chymopapain and glycosaminoglycan is important to the action of injected enzyme were not supported by the finding that both positively and negatively charged forms of chymopapain efficiently released glycosaminoglycan from cartilaginous tissue. In contrast, cysteine alone did not cause release of glycosaminoglycan. Chymopapain was found to be inhibited efficiently by the protein inhibitors, cystatin C and low molecular weight kininogen in vitro, and the possible relevance of this finding to the efficacy and safety of chemonucleolysis is discussed.

Cartilage↗
PubMed1986

Mechanism of action of intradiscal chymopapain in the treatment of sciatica: a clinical, biochemical, and radiological study.

Seventeen patients with intractable sciatica due to prolapse of a lumbar disc, treated by intradiscal injection of chymopapain (chemonucleolysis) were studied. Analysis of serial 24 hour urine collections showed a significant increase in urinary glycosaminoglycan after chemonucleolysis. This was not detected in four patients undergoing routine discography. Enzymic analysis of urinary glycosaminoglycan after chemonucleolysis suggested that the increase in levels was largely due to an increase in the amounts of chondroitin sulphate present, probably resulting from proteoglycan breakdown in the intervertebral disc. Eight of the patients treated by chemonucleolysis underwent serial computed tomography (CT). One month after the injection the only change seen was a loss of definition of the disc prolapse, which could be interpreted as a loss of turgidity in the disc as a result of proteoglycan breakdown by chymopapain. By six months the CT of those patients whose symptoms had improved showed that the degree of disc prolapse was usually less marked and the disc margin more clearly defined, suggesting that by this stage anatomical remodelling had occurred.

Adolescent↗
PubMed1985

The proteolytic activities of chymopapain, papain, and papaya proteinase III.

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.

Albumins↗
PubMed1984

Chymopapain. Chromatographic purification and immunological characterization.

Chymopapain (EC 3.4.22.6) was purified from commercially available spray-dried latex of papaya (Carica papaya) fruit by (NH4)2SO4 fractionation and fast protein chromatography on the Mono S cation-exchange column. Multiple forms of chymopapain separated chromatographically were shown to be immunologically identical. A major form was isolated and found to be homogeneous by several criteria, and fully active, and its N-terminal amino acid was identified as tyrosine. Latex from fresh unripe papaya fruit contained predominantly one form of chymopapain, and it is concluded that chymopapain is a single enzyme distinct from the other cysteine proteinases of C. papaya latex.

Amino Acids↗
PubMed1984

Epidermis promotion of collagenase in hypertrophic scar organ culture.

The pathophysiological biology of human hypertrophic scar was examined in a long-term organ culture system. Fresh full-thickness, thin slices of scar were placed in petri dishes. Tissue was successfully maintained for 2 weeks in an environment made up of CMRL-1066 medium, fetal bovine serum, insulin, and hydrocortisone under an environment of 40% O2, 5% CO2, and 55% N2 at 37 degrees C on a rocking platform. Histologically the explants were viable and remained differentiated. The omission of hydrocortisone caused localized destruction of the connective tissue matrix under the epidermal layer. Transplanting the epidermis to the adipose surface of an explant before culturing in hydrocortisone-free medium, produced localized connective tissue matrix destruction only within the deep dermal layer. Removal of the epidermis before culturing in hydrocortisone-free medium produced no localized connective tissue matrix destruction. Culture medium from intact explants maintained in hydrocortisone-free media had higher levels of latent collagenase activity compared to epidermal free explants and intact explants in hydrocortisone-containing medium. This hypertrophic scar latent collagenase had a molecular weight estimated to be 33,000 by molecular-sieve chromatography. The active form of the enzyme had a molecular weight estimated to be 26,000. When examined by gel electrophoresis, activated collagenase cleaved types I and III native collagens, producing TC-A peptide fragments of alpha chains. Type V collagen was not cleaved by this enzyme. Metal chelators such as 1,10-phenanthroline blocked enzymatic activity. Serine and sulfhydryl proteolytic inhibitors showed no effects. Intact hypertrophic scar has the capacity to produce collagenase which appears responsible for the destruction of the connective tissue matrix of the scar. The production of hypertrophic scar collagenase is somehow controlled by the epidermis.

Cicatrix↗