Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.32 (bromelain)
 1,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Young adult Sprague-Dawley rats were partially hepatectomized (two-thirds organ removal) and administered a basal diet supplemented with various animal- and plant-derived enzymes (trypsin, alpha-chymotrypsin, pepsin, lipase, alpha-amylase, malt diastase, ficin and bromelain) over a post-operative period of up to 10 days. Porcine or bovine dialyzed and lyophilized crystalline trypsin products containing 2400-3200 NF u/mg in addition to enteric-coated tablets with trypsin to chymotrypsin in a ratio of 6:1, were tested at supplementary levels of up to 4980 u/g ration. With the weight of tissue regenerated or the liver increment as indicator, trypsin in excess of 1000-1200 u/g ration proved inhibitory. This effect did not extend to alpha-chymotrypsin (levels of up to 4000 u/g diet) and the remaining 6 enzyme products specified above, nor to the s.c. injection of trypsin daily at 12,860 u/rat for the 1st 7 days. The last route promoted little change in increment with soy bean trypsin inhibitor (8.0 mg/rat daily for days 1 to 9). When a portion of the group fed a trypsin supplement of 2000 u/g was injected with phenobarbital i.p. at 80 mg/kg daily on each of the last 3 days, the resulting liver increment rose to the control range. As with lysine and arginine, acids of pertinence in tryptic proteolysis, no significant change was elicited by feeding a diet supplemented with peptone from tryptic digestion of casein. The enzyme-containing diets fed to sham-operated rats over a similar interval, did not affect the wet- or dry-liver weight per 100 g body weight. Microsomal parameters as total protein, cytochrome P-450 and the enzymes, aminopyrine demethylase and benzo[a]pyrene hydroxylase of livers from the partially hepatectomized or sham-operated rats fed trypsin and the other enzyme diets, presented no significant changes in the respective levels. The possible action of dietary trypsin in conjunction with inhibitors and growth factors controlling liver regeneration is discussed.
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PMID:Liver regeneration in trypsin-fed partially hepatectomized rats. 843 34

A new proteolytic assay is described involving Coomassie blue. Under specified conditions, the amount of Coomassie-stained casein protein hydrolyzed by several proteases was proportional to the amount of protease. Coomassie dye reaction was used directly to determine the change in protein concentration of the substrate casein during proteolysis by three proteases: stem bromelain, papain, and trypsin. This method can be used with 0.1- to 0.5-micrograms quantities of protease. The dye reagent was used directly on the protease protein in order to obtain an assay of autodigestion. Autodigestion of bromelain at 50 and 25 degrees C was followed by measuring the amount of residual protease protein with time.
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PMID:Protease activity and autodigestion (autolysis) assays using Coomassie blue dye binding. 848 11

The plasma kininogens, high (HK) and low (LK) molecular weight kininogens, are the parent proteins for bradykinin, a potent vasoactive peptide that locally influences vascular biology. Binding of both HK and LK to the endovascular wall contributes to bradykinin delivery. Recently, we found one preparation of LK (LKd) which had reduced inhibition of biotin-HK binding to endothelium. The functional defect in LKd was not merely due to bradykinin loss because two preparations of bradykinin-free LK blocked biotin-HK binding. However, using two different particular monoclonal antibodies to bradykinin, LKd, but no other preparation of LK, had its epitope to bradykinin exposed on non-reduced samples on immunoblot. These data suggested that LKd had an altered conformation which exposed the amino terminal arginine of bradykinin to antigenic detection. The altered conformation of LKd allowed it to be more susceptible to trypsin proteolysis. On circular dichroism, the percentage of alpha-helix was significantly increased, indicating an alteration in the protein. This alteration in LKd was not due to a loss of molecular mass of the protein. On laser desorption mass spectroscopy, the molecular mass of LKd was similar to the other preparations of LK. Investigations were performed to ascertain the mechanism by which LKd had altered ability to bind to cells. LKd was found to be proteolyzed by an unknown protease at the beginning of domain 2 between threonine119 and alanine120. Reduction of functional LK with dithiothreitol to expose its bradykinin epitope did not produce the LKd defect. Proteolysis of functional LK with plasma kallikrein, elastase followed by plasma kallikrein, chymotrypsin, or bromelain also did not produce the defect seen in LKd. These combined data indicated that LK maintains a particular conformation that allows the protein to orient itself such that it can bind to endothelial cells. Proteolysis in the surface exposed region between domains 1 and 2 probably allows for the protein to unfold and contributes to its lost ability to bind to endothelial cells.
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PMID:Conformational changes in low molecular weight kininogen alters its ability to bind to endothelial cells. 856 Apr 18

Bromelain inhibitor VI from pineapple stem (BI-VI) is a unique double-chain inhibitor with an 11-residue light chain and a 41-residue heavy chain by disulfide bonds and inhibits the cysteine proteinase bromelain competitively. The structure of BI-VI in aqueous solution was determined using nuclear magnetic resonance spectroscopy and simulated annealing-based calculations. Its three-dimensional structure was shown to be composed of two distinct domains, each of which is formed by a three-stranded antiparallel beta-sheet. Unexpectedly, BI-VI was found to share a similar folding and disulfide bond connectivities not with cystatin superfamily inhibitors which inhibit the same cysteine proteinases but with the Bowman-Birk trypsin/chymotrypsin inhibitor from soybean (BBI-I). BBI-I is a 71-residue inhibitor which has two independent inhibitory sites toward the serine proteinases trypsin and chymotrypsin. These structural similarities with BBI-I suggest that they have evolved from a common ancestor and differentiated in function during a course of molecular evolution.
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PMID:Solution structure of bromelain inhibitor IV from pineapple stem: structural similarity with Bowman-Birk trypsin/chymotrypsin inhibitor from soybean. 861 27

We have used rabbit polyclonal antisera raised against synthetic peptides complementary to different domains of the Rh polypeptides and Rh glycoprotein to examine the topography and organization of these proteins in the human erythrocyte membrane. Previously unrecognized exofacial protease sites have been identified on Rh CcEe, D proteins, and Rh glycoprotein. The Rh D protein has two specific bromelain cleavage sites located within the first and sixth predicted external domains, with the site of cleavage localized in the sixth domain to lie between residues 353 and 354. All Rh polypeptide species were found to be susceptible to cleavage with trypsin and subtilisin within the first external domain of these proteins. The Rh glycoprotein has two bromelain cleavage sites within the first external domain. These flank the single N-glycosylation site (Asn37), with the cleavage site toward the C-terminal side of this residue being between residues 39 and 40. Bromelain treatment was found to deglycosylate the Rh glycoprotein. Immunoprecipitation experiments have revealed that anti-C, -c,E, -e, and -D immune complexes are reactive with antisera raised against the fourth predicted external loop of the Rh proteins and the C-terminal domain. These data indicate that the hypothesis that suggests Rh C/c antigens are expressed on truncated Rh polypeptides by a mechanism of alternate splicing is incorrect and support the hypothesis that Rh Cc and Ee antigens are expressed on a single polypeptide chain.
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PMID:Immunochemical analysis of the human erythrocyte Rh polypeptides. 866 3

The alpha-macroglobulin proteinase inhibitors (alpha Ms) are a family of proteins with the unique ability to inhibit a broad spectrum of proteinases. Whereas monomeric, dimeric and tetrameric alpha Ms have been identified in vertebrates, all invertebrate alpha Ms characterized so far have been dimeric. This paper reports the isolation and characterization of a tetrameric alpha M from the tropical planorbid snail Biomphalaria glabrata. The sequence of 18 amino acids at the N-terminus indicates homology with other alpha Ms. The subunit mass of approx. 200 kDa was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and SDS/PAGE. The quaternary structure was determined by sedimentation equilibrium centrifugation and native pore-limit electrophoresis. Evidence for a thioester is provided by the fact that methylamine treatment prevents the autolytic cleavage of the snail alpha M subunit and results in the release of 4 mol of thiols per mol of snail alpha M. The snail alpha M inhibited the serine proteinase trypsin, the cysteine proteinase bromelain and the metalloproteinase thermolysin. The spectrum of proteinases inhibited, together with the demonstration of steric protection of the proteinase active site and a "slow to fast' conformational change after reacting with trypsin, all suggest that the inhibitory mechanism of the snail alpha M is similar to the "trap mechanism' of human alpha 2-macroglobulin.
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PMID:Purification and characterization of a tetrameric alpha-macroglobulin proteinase inhibitor from the gastropod mollusc Biomphalaria glabrata. 867 Jan 68

Recently it has been shown that protease therapy ameliorates certain immune-mediated diseases. Thus we studied the effect of administration of a protease mixture on aortic transplant arteriosclerosis in rats. Segments of abdominal aorta from SHR strain were transplanted orthotopically into WKY recipients. Two groups of allografted rats were used. One group (n = 8) was treated with daily intraperitoneal injections of 12 mg of a protease formulation containing trypsin, bromelain and rutosid, and another group (n = 8) with placebo. Eight WKY rats were transplanted with syngenic aortas and treated with placebo. After 8 weeks, structural changes of the grafted segment were evaluated by morphometric analysis of formalin-fixed sections with specific stains. In untreated allografts there was a marked intimal thickening, medial necrosis with disruption of elastic fibres, and inflammatory infiltrates in the adventitia. Administration of proteases inhibited formation of neointima by 59.0% when cross-sectional areas were compared (80+/-11 versus 195+/-11 microm2, P<0.01; protease-versus placebo-treated allograft recipients respectively) and decreased medial injury as estimated by the integrity of elastic fibres and smooth-muscle cell density. Thus, in an experimental model of rat aortic allograft, protease administration ameliorates rejection-induced arterial wall remodelling.
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PMID:Beneficial effect of proteases on allograft arteriosclerosis in a rat aortic model. 867 57

The hepatitis B viruses replicate by reverse transcription of an RNA pregenome by using a virally encoded polymerase. A key early step in replication is binding of the polymerase to an RNA stem-loop (epsilon) of the pregenome; epsilon is both the RNA encapsidation signal and the origin of reverse transcription. Here we provide evidence that this interaction is also key to the development of enzymatic activity during biosynthesis of the polymerase. Duck hepatitis B virus polymerase expressed in Saccharomyces cerevisiae can synthesize DNA from epsilon-containing RNAs and can also end label other small RNAs. Expression of functional polymerase in S. cerevisiae requires interaction between the polymerase and epsilon during or shortly after translation for it to develop any enzymatic activity; if epsilon is absent during expression, the polymerase is inactive on RNAs both with and without epsilon. Functional duck polymerase can also be produced by in vitro translation, and synthesis of the polymerase in the presence of epsilon induces resistance in the polymerase to proteolysis by papain, trypsin, and bromelain. Induction of the resistance is specific for epsilon sequences that can support RNA encapsidation and initiation of DNA synthesis. Induction of the resistance precedes initiation of DNA synthesis and is reversible by degradation of epsilon. These two sets of data (i) support a model in which binding of epsilon to the polymerase induces a structural alteration of the polymerase prior to the development of enzymatic activity and (ii) suggest that this alteration may be required for the polymerase to mature to an active form.
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PMID:Evidence for activation of the hepatitis B virus polymerase by binding of its RNA template. 870 89

This work represents our first step toward fulfilling the need to discover a model system for experimental investigations of temporal oscillations, pattern formations, and other non-linearity related dynamic behavior in immobilized-enzyme-membrane systems. In this paper, the regions in the parameter space where self-sustained pH oscillations can be induced were determined via extensive numerical simulation for five enzyme-membrane systems involving four proteolytic enzymes: alpha-chymotrypsin, trypsin, bromelain, and ficin. From this study, we concluded that, even with current enzyme-immobilization techniques, the possibility of experimentally observing self-sustained pH oscillations in a flat membrane immobilized with alpha-chymotrypsin and using N-acetyl-L-tryptophan ethyl ester as a substrate is high. Under suitable conditions and with extra efforts, self-sustained oscillations may also occur in membrane systems immobilized with ficin, trypsin and bromelain.
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PMID:Self-sustained pH oscillations in immobilized proteolytic enzyme systems. 886 29

Native tubulin alpha beta dimers and microtubules have been subjected to limited proteolysis with trypsin, chymotrypsin, elastase, clostripain, proteinase lysine-C, thermolysin, protease V8, papain, subtilisin, proteinase K, proteinase aspartic-N, and bromelain. Eighty nicking points have been mapped onto the alpha- and beta-tubulin sequences with the aid of site-directed antibodies, of which 18 sites have been exactly determined by N-terminal sequencing, and the probable position of 6 others deduced from protease specificities. Proteolytic sites cluster into five characteristic zones, including the C termini of both chains. Residues accessible to proteases in the tubulin dimer include alpha-tubulin Lys40-Thr41-Ile42, Glu168-Phe169-Ser170, Ser178-Thr179-Ala180-Val181, Lys280-Ala281, Glu290-Ile291, Ala294-Cys295, Arg339-Ser340 (plus probably Lys60-His61 and Glu183-Pro184) and beta-tubulin Gly93-Gln94, Lys174-Val175, Gly277-Ser278, Tyr281-Arg282-Ala283, Cys354-Asp355 (plus probably Arg121-Lys122, Phe167-Ser168, Tyr183-Asn184, and Glu426-Asp427 or Ala430-Asp431). While the majority of these sites remain accessible at the outer surface of taxol-induced microtubules, alpha-tubulin Lys280-Ala281, Arg339-Ser340 and beta-tubulin Tyr281-Arg282-Ala283 (and probably Arg121-Lys122) become protected from limited proteolysis, suggesting that they are close to or at intermolecular contacts in the assembled structure. The protease nicking points constitute sets of surface constraints for any three-dimensional model structures of tubulin and microtubules. The dimer tryptic site at alpha-tubulin 339-340 jumps approximately 12-22 residues upstream (probably to Lys326-Asp327 or Lys311-Tyr312) in taxol microtubules, suggesting a tertiary structural change. The cleavage of the approximately 10 C-terminal residues of alpha-tubulin by protease V8, papain, and subtilisin is inhibited in taxol microtubules compared to tubulin dimers, while the approximately 20 C-terminal residues of beta-tubulin are similarly accessible to protease V8, subtilisin, proteinase K, proteinase AspN, and bromelain and show enhanced papain cleavage. This is consistent with models in which the alpha-tubulin C-terminal zone is near the interdimer contact zone along the protofilaments, whereas the C terminus of beta is near the interface between both subunits.
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PMID:Mapping surface sequences of the tubulin dimer and taxol-induced microtubules with limited proteolysis. 891 4


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