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)

gamma-Glutamyl transpeptidase is associated with the membranes of a number of epithelial and lymphoid cells. When the enzyme is isolated from rat kidney by a method involving detergent extraction and affinity chromatography, an aggregate of molecular weight greater than 200,000 (heavy form) is obtained. Treatment of the heavy form with bromelain yields a light form of the enzyme (molecular weight of approximately 68,000), which is separable by isoelectric focusing into 12 enzymatically active isozymes which are very similar with respect to catalytic behavior, content of amino acids, hexoses, and aminohexoses, but which differ significantly in sialic acid content. Treatment with neuraminidase converts the acidic isozymes to more basic forms. Each isozyme dissociates in sodium dodecyl sulfate into two nonidentical glycopeptides (molecular weights of 46,000 and 22,000) which can be cross-linked with dimethylsuberimidate to yield a species with an apparent molecular weight of 70,000, which indicates that the isozymes are dimers. Physical and immunological studies indicate that the heavy form of the enzyme contains the dimeric light form as well as other membrane proteins.
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PMID:Subunit structure and isozymic forms of gamma-glutamyl transpeptidase. 0 76

Haemagglutinin released from influenza A virus recombinant MRC11 [antigenically identical to the strain A/Port Chalmers/1/73 (H3N2)] by bromelain treatment and purified by rate zonal centrifugation (further on B-HA) was examined for eventual contamination by neuraminidase. According to specific enzymatic activities corresponding to MRC11 virus and B-HA alone respectively, B-HA contained less than 0.1% of enzymatically active neuraminidase orginally present in the virus. Gel double diffusion tests, specifities of rabbit antisera induced by B-HA, as well as radioimmunoprecipitation experiments demonstrated that B-HA was devoid of any antigenically active neuraminidase. Precipitation of 125I-labelled B-HA with antisera to influenza virus recombinants with N2 neuraminidase has been evidently caused by antibodies to host antigenic determinaant(s) present in these sera. With respect to purity as well as radioimmunoprecipitation properties, B-HA is quite suitable for radioimmunoassay experiments.
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PMID:Radioimmunoassay of influenza A virus haemagglutinin. I. Preparation and properties of radioactive 125I-labelled bromelain-released haemagglutinin. 2 2

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (H0N1) and A/Bel/42 (HO)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. In several cases, the quantity of AN antibody formation depended on the hemagglutinin (HA) dose present in the vaccines. The N2 NA on the recombinant virus was significantly more sensitive to treatment with reducing agent than was the N2 NA on the parent virus. AN antibodies directed against N2 NA on the recombinant differed qualitatively from that directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.
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PMID:Preparation-conditioned changes of the antigenicity of influenza virus neuraminidases. 6 66

The ascites form of a chemically induced guinea pig hepatoma, line-10, was resistant to killing in vitro by xenogeneic antibody and guinea pig complement. Pretreatment of line-10 cells with certain proteolytic enzymes rendered tham susceptible to the killing action of antibody and guinea pig complement. The effects of enzyme pretreatment were dependent on enzyme concentration, temperature, and could be blocked by addition of competitive or non-competitive inhibitors. The effect of the enzyme treatment could reversed by incubating the treated cells at 37 degrees C (but not at 0 degrees C), in the absence of the enzyme. Effective enzymes included ficin, bromelain, pronase, elastase, papain, trypsin, collagenase, lipases type I and type VI, and the neuraminidase preparation isolated from Clostridium perfringens. The activity of the lipase preparations and the neuraminidase preparation isolated from Clostridium perfringens appeared to be caused by proteolytic enzyme contamination. Enzyme preparations that proved ineffecitve in rendering the line-10 cells sensitive to killing by antibody and guinea pig complement included DNase, RNase, beta-glucuronidase type 6A or type B10, hyaluronidase type V or type VI, and pectinesterase.
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PMID:Lysis of tumor cells by antibody and complement. VI. Enhanced killing of enzyme-pretreated tumor cells. 17 70

We have observed that treatment of rabbit synovial fibroblasts with proteolytic enzymes can induce secretion of collagenase (EC 3.4.24.7) and plasminogen activator (EC 3.4.21.-). Cells treated for 2-24 hr with plasmin, trypsin, chymotrypsin, pancreatic elastase, papain, bromelain, thermolysin, or alpha-protease but not with thrombin or neuraminidase secreted detectable amounts of collagenase within 16-48 hr. Treatment of fibroblasts with trypsin also induced secretion of plasminogen activator. Proteases initiated secretion of collagenase (up to 20 units per 10(6) cells per 24 hr) only when treatment produced decreased cell adhesion. Collagenase production did not depend on continued presence of proteolytic activity or on subsequent cell adhesion, spreading, or proliferation. Routine subculturing with crude trypsin also induced collagenase secretion by cells. Secretion of collagenase was prevented and normal spreading was obtained if the trypsinized cells were placed into medium containing fetal calf serum. Soybean trypsin inhibitor, alpha(1)-antitrypsin, bovine serum albumin, collagen, and fibronectin did not inhibit collagenase production. Although proteases that induced collagenase secretion also removed surface glycoprotein, the kinetics of induction of cell protease secretion were different from those for removal of fibronectin. Physiological inducers of secretion of collagenase and plasminogen activator by cells have not been identified. These results suggest that extracellular proteases in conjunction with plasma proteins may govern protease secretion by cells.
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PMID:Proteases induce secretion of collagenase and plasminogen activator by fibroblasts. 20 72

Sigma bromelain (EC 3.4.22.4) was used to isolate the haemagglutinin (HA) from the MRC-11 (H3N2) and A/U.S.S.R./90/77 (H1N1) influenza A virus strains. Sedimentation analysis of bromelain-solubilized preparations revealed 9.5S and 5.5S protein components, the former being identified as the bromelain-released haemagglutinin (BHA). No residual neuraminidase (NA) activity was detected in the BHA isolated from the MRC-11 strain whereas up to 80 per cent of the enzymatically active NA was found to be preserved in the electrophoretically pure BHA isolated from the A/U.S.S.R./90/77 strain. Increased electrophoretic mobilities were exhibited by both the light and heavy chains of the BHA subunit. The difference observed in the molecular weights of the polypeptide fragments removed by bromelain from the light chains is interpreted in terms of the different depth of penetration of antigenically distinct HAs through the influenza virus lipid membrane. Splitting off of approximately 15 and 26 per cent of the sugars from the carbohydrate portions of the light and heavy chains respectively, was demonstrated. This suggested involvement of glycosidase impurities present in the bromelain preparation employed. The rod-shaped BHA molecules proved to be 110 +/- 5 Angstrom long and 40 +/- 5 Angstrom wide as measured by electron microscopy. It is proposed that the 45,000-molecular-weight polypeptide observed constantly in egg-grown influenza viruses is host actin.
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PMID:Structure of bromelain-released influenza virus haemagglutinin as revealed by electrophoresis, sedimentation and electron microscopy. 54 1

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (HoN1) and A/Bel/42 (Ho)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. AN antibodies directed against N2 NA on the recombinant differed qualitatively from those directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.
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PMID:[Changes in the antigenicity of influenza virus neuraminidases due to various methods of preparation]. 62 93

The organization of the lipid bilayer of the enveloped Sindbis virus has been studied. In the model membrane which consists only of two virus specific glycoproteins and host derived lipids the latter were radioactively labelled with 14C-palmitic acid by prelabelling their BHK 21 host cell lipids. The purified virus particles were submitted to neuramidase, bromelain and combromelain-neuraminidase treatment. It could be demonstrated that N-acetyl neuraminic acid residue of the total hematoside present in the virion is hydrolyzed by neuraminidase leaving the particles fully intact. Proteolysis of the spikes leads to particle aggregation yet an unchanged hematoside content. This was fully transformed into ceramidelactoside by subsequent neuraminidase treatment. The analyses of the ceramide species present in hematoside of the control particles and ceramidelactoside derived thereof by neuraminidase hydrolysis are in very close agreement. From these experiments it is concluded that all hematoside molecules are organized in the outer half of the bilayer of the envelope.
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PMID:Asymmetry of the lipid-bilayer of Sindbis virus. 99 84

Although neutrophils are not viewed as a principal defense against influenza A virus (IAV) infection, their interactions are both complex and clinically relevant. Activation of the neutrophil is distinctive from that described for chemoattractants. To more fully characterize the pathway by which IAV stimulates the human neutrophil, we have examined its binding characteristics. First, inhibition studies with various sialic acid-containing and sialic-free sugars showed that IAV binds to sialic acid residues and activates receptors distinct from those used by Concanavalin-A (Con-A) and formyl-methionyl-leucyl-phenylalanine (FMLP) and that overlap those bound by wheat germ agglutinin (WGA). That viral hemagglutinin (HA) mediates viral binding and activation was shown by preincubating neutrophils with purified monovalent bromelain-released HA (BHA) and showing that IAV-induced membrane depolarization and hydrogen peroxide (H2O2) production were inhibited approximately 95%. However, binding inhibition required significantly higher concentrations of purified HA, suggesting that binding and cell activation have different interactive requirements. Desialation of the neutrophil surface membrane by neuraminidase treatment resulted in a 90.6% +/- 4.4% and 53.1% +/- 8.7% inhibition of IAV activation of neutrophils and viral binding, respectively. Resialation with ganglioside GT1b totally restored viral binding, but did not reverse the inhibition of activation. Thus, although HA was shown to mediate binding and neutrophil activation, viral binding per se was insufficient to stimulate the cell. Having demonstrated the functional role of HA, we sought to establish the mechanism of stimulation. HA in three different forms (BHA, HA-rosettes, and HA-liposomes) failed to activate the cell, although H2O2 production evoked by IAV stimulation was reduced in competitive inhibition studies with each preparation. Upon cross-linking with a monoclonal antibody to HA, activation comparable to that of intact virus was observed. The requirement for cross-linking of functional receptors, as opposed to activation through the neutrophil Fc receptor, was confirmed in experiments using staphylococcal A protein. These studies have shown the chemical specificity of IAV binding to the human neutrophil, the character of the receptor(s) stimulated to activate the IAV-evoked response, and the activation requirement for cross-linking those receptors responsible for stimulating functional responses.
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PMID:Influenza A virus binding to human neutrophils and cross-linking requirements for activation. 133 33

Ultraviolet light-inactivated, non-infectious influenza virus is pyrogenic; virion components are probably responsible for this pyrogenicity. To try to identify the pyrogenic component, influenza virions were disrupted with either bromelain or sodium deoxycholate (DOC). Treatment of infectious virions with bromelain, under conditions that removed the surface glycoproteins (spikes), destroyed their pyrogenicity. The supernatant, containing non-aggregated and modified glycoproteins, was also non-pyrogenic. Disruption of virions with DOC considerably reduced pyrogenicity; however, some was retained by the sub-viral cores. Viral nucleoprotein and matrix protein, purified from the supernatant, were non-pyrogenic. Aggregated stellate clusters of surface glycoproteins separated on sucrose gradients were pyrogenic in half of numerous tests performed with different batches of material. Treatment of virus with ether resulted in complete loss of pyrogenicity. Liposomes made from extracted viral lipid were non-pyrogenic. In contrast, virosomes made from the viral lipid and the aggregated stellate clusters of surface glycoproteins were pyrogenic. Hence, optimum pyrogenicity depends upon the integrity of the virus particle, but haemagglutinin and/or neuraminidase appear essential, and lipid may be involved.
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PMID:Influenza virus pyrogenicity: central role of structural orientation of virion components and involvement of viral lipid and glycoproteins. 160 57


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