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

1 In atrial preparations of the young guinea-pig (body weight 150-250 g), five proteolytic enzymes (trypsin, chymotrypsin, bacterial-Al-proteinase (nagarse), bromelain and kallikrein) produced concentration-dependent positive inotropic and chronotropic effects, while they exerted only minimal effects on the papillary muscle preparations. 2 To characterize the effects, further experiments were conducted in atrial preparations using trypsin. There was a strong tendency for tachyphylaxis: a second exposure to the same concentration of trypsin resulted in considerably smaller positive inotropic and chronotropic effects. The positive inotropic and chronotropic effects of this substance were not affected by propranolol (5 X 10(-7)M). However, an accumulation of cyclic AMP was observed and the positive inotropic and chronotropic effects were potentiated by aminophylline (10(-4)M) in association with an augmentation of the accumulation of cyclic AMP. In preparations partially depolarized with high K+ (22mM) medium (contractions ceased under this condition) trypsin 100 micrograms ml-1 reinstated the contraction. Treatment of the preparation with aprotinin (200 u ml-1) resulted in a strong inhibition of the positive inotropic and chronotropic effects. 3 Islet activating protein (IAP), a specific inhibitor of the 'inhibition specific' guanine nucleotide binding regulatory protein of the adenylate cyclase system, did not produce significant inhibition of the positive inotropic and chronotropic effects of trypsin, whereas it produced a complete inhibition of the negative inotropic and chronotropic effects of carbachol. 4. These results suggest that the positive inotropic and chronotropic effects ofproteolytic enzymes are intimately connected with the proteolytic activities through which adenylate cyclase is activated to produce an accumulation of cyclic AMP within the myocardium. The destruction of the 'inhibition specific' guanine nucleotide regulatory protein of the adenylate cyclase was not substantiated as a mechanism of activation of the adenylate cyclase.
Br J Pharmacol 1987 Sep
PMID:Positive inotropic and chronotropic effects of trypsin and some other proteolytic enzymes in the guinea-pig heart. 331 Dec 66

The frequency of splenic B cells producing antibodies reactive with bromelain-treated mouse red blood cells (BrMRBC) or T cell surface antigens was examined in autoimmune and normal mice. This was accomplished by fixing target cells to microtiter plates such that their membrane antigens could be detected in ELISA and ELISA-spot assays. This technique was rapid, sensitive, and permitted antibodies of both the IgG and IgM isotypes to be measured independently. Autoimmune NZB, BXSB male and MRL-lpr/lpr mice had 10-100-fold higher levels of serum anti-BrMRBC and anti-T cell antibodies than did control DBA/2 and CBA/J animals. The frequency of splenic B cells producing autoantibodies of these specificities was similarly increased among autoimmune mice. In general, the number of antibody-forming cells (AFC) reactive with BrMRBCs was 2-5 times higher than the number reactive with T cell surface determinants. In NZB mice these cells produced primarily IgM autoantibodies whereas in MRL-lpr/lpr animals they secreted primarily IgG. The concentration of serum autoantibody did not precisely correlate with AFC frequency, indicating that immunoglobulin catabolism and other factors play a role in regulating serum antibody concentration.
J Immunol Methods 1987 Sep 24
PMID:Novel ELISA and ELISA-spot assays used to quantitate B cells and serum antibodies specific for T cell and bromelated mouse red blood cell autoantigens. 349 72

Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either 3H-fatty acids or [3H]ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the 3H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of [3H]ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from 3H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the 3H-fatty acid and the [3H]ethanolamine label from the purified alkaline phosphatase. Subtilisin was also able to remove the [3H]ethanolamine-labeled from purified alkaline phosphatase. The 3H radioactivity in alkaline phosphatase purified from [3H]ethanolamine-labeled cells comigrated with authentic [3H]ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the 3H-fatty acid and [3H]ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase.
Biochemistry 1987 Sep 08
PMID:Phosphatidylinositol anchor of HeLa cell alkaline phosphatase. 367 79

A polypeptide proteinase inhibitor from human articular cartilage has been purified to homogeneity by stepwise Sephadex G-75, heparin-Sepharose and octyl-Sepharose affinity chromatography. The inhibitor is strongly cationic (pI greater than or equal to 10.5) and consists of two non-identical polypeptides associated by means of electrostatic and/or hydrophobic interactions. Amino acid analysis of the aggregate confirmed that the polypeptide was rich in basic, and hydrophobic amino acids and contained only one disulphide bridge. Sedimentation equilibrium studies showed that the aggregate had MW congruent to 7000 which could be dissociated into two polypeptides each of MW congruent to 3500. While the subunits were primarily serine proteinase inhibitors the aggregate form could also inhibit bacterial collagenase and pepsin but not thermolysin nor the cysteine proteinases, ficin or bromelain. Binding of 125I-labelled human cartilage inhibitor to heparin, keratan sulphate and proteoglycan subunit was demonstrated using gel exclusion chromatography but no interaction was detected with chondroitin 6-sulphate or hyaluronic acid. Binding of cartilage inhibitor subunits to link proteins was also shown by polyacrylamide electrophoresis. These data suggest that the human cartilage inhibitor may be localised at specific sites on the proteoglycan complex where it would be ideally placed to attenuate degradation by matrix proteinases or constitute part of an enzyme-inhibitor complex.
Biochim Biophys Acta 1984 Sep 25
PMID:Polypeptide proteinase inhibitor from human articular cartilage. 638 79

Incubation of guinea pig lung mitochondrial suspension in an isotonic low ionic strength buffer containing various proteolytic enzymes caused significant stimulation of the glycerophosphate acyltransferase activity. The maximal stimulation range between 20 and 105%, and the order was as follows: bromelain greater than chymotrypsin greater than pronase greater than trypsin greater than papain greater than nagarse. Under hypotonic conditions, over 85% of GAT was destroyed by all the proteolytic enzymes. Microsomal enzyme activity was consistently inhibited (greater than 95%) by exposure to any of these proteases even under isotonic conditions. These results suggest that GAT is located on the inner aspect of the mitochondrial outer membrane. Also, it is likely that a portion of this enzyme or that of a modulator is present in the outer side of the outer membrane and proteolysis of this component causes stimulation.
Biochem Biophys Res Commun 1984 Sep 17
PMID:Location of glycerol phosphate acyltransferase in the transverse plane of mitochondrial outer membrane of guinea pig lung. 638 69

The brush border of the enterocytes of the rat was isolated by the method of differential centrifugation with CaCl2 according to Schmitz. This material was solubilized with papain, trypsin and Triton X-100. The greatest amount of membrane enzymes was released to the supernatant (105 000 X g) with the use of Triton X-100. The tritonized supernatant was treated in the next step by papain, bromelain, ficin and trypsin (individually or in combinations). After simultaneous proteolysis with papain and bromelain a partial separation of the aminopeptidase from the endopeptidase by Sephadex G-200 chromatography was observed. These two enzyme activities were distinctly separated by isoelectric focusing at pH 4--6. Two enzymatically active bands (RF 0.13 and 0.24) in the aminopeptidase fraction and one single active band (RF 0.16) in the endopeptidase fraction using polyacrylamide gel electrophoresis were found. Co-migrating proteins to all of these activities were detected. Endopeptidase activity splits 3-carboxypropionyltrialanin-4-nitroanilide (SucAla3NAp) in the position P2-P1. Liberated aminoacyl-NAP may be further split to generate chromogenic 4-nitroaniline through aminopeptidase activity. Endopeptidase of the brush border of the rat enterocytes is characterized by the following properties: 1) molecular mass 130000 +/- 15 000 dalton; 2) Km value (substrate: SucAla3NAp) 1.1 X 10(-3) M; 3) pI 5.23; 4) ph optimum 8.5; 5) 50% activity remains after 15 min of preincubation at 50 degrees C; 6) activity is strongly inhibited by EDTA, p-chloromercuribenzoate, Mn2 and Co2.
Hoppe Seylers Z Physiol Chem 1980 Sep
PMID:Endopeptidase of the brush border membrane of rat enterocyte. Separation from aminopeptidase and partial characterization. 700 58

Different clones of mouse hybridomas, derived from the fusion of unstimulated mouse peritoneal cells with mouse myeloma cells, producing IgM monoclonal antibodies directed against the membrane of bromelain-treated mouse erythrocytes (MRBC(Br)) have been previously established. We have recently shown that one of these hybridomas produce, in ascites, antibodies cross-reacting with phosphorylcholine derivatives (trimethylammonium (TMA) derivatives). In this work the cross-reactivity for TMA derivatives of the monoclonal antibodies produced by 4 anti-MRBC(Br) hybridomas have been studied at the cell level (plaque-forming cells). Phosphorylcholine, choline bromide and p-aminophenyl-trimethylammonium were found to be potent specific inhibitors of plaque formation (anti MRBC(Br)). The hemolytic activities of ascites and tissue culture supernatants were studied and their inhibition by TMA derivatives was determined. Immunoglobulins from ascites purified on TMA immunoadsorbent column were analyzed by two-dimensional gel electrophoresis, their spectrotype was compared to the spectrotype of immunoglobulins from tissue culture supernatants from the same hybridoma radioactively tagged by internal incorporation of [14C]leucine. It could be shown without ambiguity that the PTMA column retained an IgM with the same characteristics as the IgM secreted in vitro.
Immunol Lett 1982 Sep
PMID:Relationship between choline derivatives and mouse erythrocyte membrane antigens revealed by mouse monoclonal antibodies. I. Anticholine activity of anti-mouse erythrocyte monoclonal antibodies. 715 55

The thiol protease bromelain has been shown to remove T-cell CD44 molecules from lymphocytes and to affect T-cell activation. We investigated the effect of a highly purified bromelain protease F9 (F9) on the adhesion of peripheral blood lymphocytes (PBL) to human umbilical vein endothelial cells (HUVEC). Preincubation of the lymphocytes with F9 reduced the adherence to about 20% of unstimulated and to about 30% of phorbol-dibutyrate (P(Bu)2) stimulated lymphocytes. Using flow cytometry, both crude bromelain and protease F9 reduced the expression of CD44, but not of LFA-1, on PBL. F9 was about 10 times more active than crude bromelain; at 2.5 micrograms/ml of F9 about 97% inhibition of CD44 expression was found. A mAb against CD44 was tested and found to block the F9-induced decrease in PBL-binding to HUVEC. The results indicate that F9 selectively decreases the CD44 mediated binding of PBL to HUVEC.
FEBS Lett 1994 Sep 05
PMID:Bromelain protease F9 reduces the CD44 mediated adhesion of human peripheral blood lymphocytes to human umbilical vein endothelial cells. 752 49

One of the bromelain inhibitors, isoinhibitor VI (BI-VI), was purified from pineapple stem powder and its complete amino acid sequence was determined by conventional protein sequencing. These results revealed that the protein consists of an 11-residue light chain and a 41-residue heavy chain, cross-linked to each other by disulfide bonds to form the native inhibitor of 52 residues (M(r) = 5888). The secondary structure of BI-VI was analyzed based on the sequence-specific 1H resonance assignment of its two-dimensional NMR spectra. BI-VI was shown to be composed of two domains (A and B) which are formed by antiparallel beta-sheets, but has no alpha-helix. These results were consistent with the CD spectra of BI-VI. Residues Lys27-Ile29 (heavy chain) form a triple-stranded antiparallel beta-sheet with residues Asp9-Tyr11 and Lys22-Glu24 (heavy chain) in the A domain and residues Cys5-Cys7 (heavy chain) form another triple-stranded beta-sheet with residues Cys6-Cys8 (light chain) and Asp32-Ile34 (heavy chain) in the B domain. The secondary structure as well as the primary structure of BI-VI was distinctly different from that of the other cysteine protease inhibitor, cystatin, and from that of basic pancreatic trypsin inhibitor.
Eur J Biochem 1995 Sep 01
PMID:Primary structure, sequence-specific 1H-NMR assignments and secondary structure in solution of bromelain inhibitor VI from pineapple stem. 755 79

Aged humans and experimental animals are impaired in their responses to most foreign antigens although they produce greater amounts of autoantibodies. We have examined the effect of age on the production of antibodies to a prototypic foreign antigen, sheep erythrocytes (SRBC), and to a prototypic autoantigen, bromelain-treated mouse erythrocytes (BrMRBC), in young and old mice before and after immunization with SRBC. Old mice express more anti-BrMRBC plaque-forming cell (PFC) antibodies before and an even greater number after immunization with SRBC than young mice. Conversely, old mice produce far fewer anti-SRBC PFC than young mice following immunization with SRBC. We hypothesized that the differences in the responses of old mice to BrMRBC and SRBC reflects differences in the activity of CD5+ and CD5- B cells. To test this hypothesis we immunized young and old mice with foreign antigens reported (and confirmed in our studies) to stimulate CD5+ B cells [TNP-ficoll and phosphorylcholine-keyhole limpet hemocyanin (KLH)] or CD5- B cells (SRBC and TNP-KLH). We found that the PFC response of old mice to antigens mediated by CD5+ B cells was equal to or greater than that of young mice. In contrast the PFC response of old mice induced by antigens mediated by CD5- B cells was only 10% that of young mice. Thus it appears that the immune response of old mice is well maintained for antigens which elicit a CD5+ B cell response but not for those which elicit a CD5- B cell response.(ABSTRACT TRUNCATED AT 250 WORDS)
Int Immunol 1993 Sep
PMID:Effect of age on the expressed B cell repertoire: role of B cell subsets. 769 39


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