Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Bacillus sp. no. AH-101 alkaline protease showed higher hydrolysing activity against insoluble fibrous natural proteins such as elastin and keratin in comparison with subtilisins and Proteinase K. The optimum pH of the enzyme toward elastin and keratin was pH 10.5 and pH 11.0-12.0 respectively. The specific activity toward elastin and keratin was 10,600 units/mg protein and 3970 units/mg protein, respectively. The enzymatic activity was not inhibited by p-chloromercuribenzoic acid and iodoacetic acid. Carbobenzoxy-glycyl-glycyl-L-phenylalanyl chloromethyl ketone completely inhibited the caseinolytic activity, but 36% elastolytic activity remained. No inhibitory effect on caseinolytic and elastolytic activity was shown by tosyl-L-phenylalanyl-chloromethyl ketone, tosyl-L-lysine chloromethyl ketone, carbobenzoxy-L-phenylalanyl chloromethyl ketone, and elastatinal. The amino acid composition and amino terminal sequence of the enzyme were determined. The no. AH-101 alkaline protease was compared with subtilisin BPN', subtilisin Carlsberg, no. 221, and Ya-B alkaline proteases. Extensive sequence homology existed among these enzymes.
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PMID:Characterization of an alkaline protease from Bacillus sp. no. AH-101. 137 8

Invasive pulmonary aspergillosis, usually caused by Aspergillus fumigatus, is a life-threatening condition of immunosuppressed patients. We have created a mutant strain of this fungus that lacks an extracellular alkaline protease (AFAlp). This was accomplished by transformation of A. fumigatus with a plasmid containing a selectable marker for hygromycin B resistance, and a 504 bp segment of the AFAlp gene, obtained by polymerase-chain-reaction-based amplification of A. fumigatus genomic DNA. Approximately 25% of transformants resulted from disruption of the AFAlp gene. SDS-polyacrylamide gel electrophoresis of proteins from the culture filtrate of a strain carrying the AFAlp gene disruption showed that it lacked a major protein of 33 kDa. Furthermore, in contrast to the culture filtrate from wild-type cells, the mutant had undetectable activity on azocollagen and elastin-Congo red, over a broad pH range. This shows that AFAlp accounts for most, if not all, of the extracellular elastinolytic activity of A. fumigatus, and that the mutant strain will be useful in assessing the role of AFAlp in pathogenicity.
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PMID:An Aspergillus fumigatus alkaline protease mutant constructed by gene disruption is deficient in extracellular elastase activity. 149 93

Aspergillus fumigatus secreted an inducible alkaline protease (AlPase) when cultivated in the presence of collagen (200 micrograms/ml) as sole nitrogen and carbon source. Proteolytic activity was maximum at pH 9.0 with azocollagen as substrate. The enzyme, which was the major protein found in the supernate of a liquid culture, was purified by ammonium sulphate precipitation and gel filtration. The Mr was determined to be 33 Kda by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The isoelectric point was estimated to be pH 8.2. Divalent cations strongly inhibited enzyme activity, whereas non-ionic detergents and reducing agents had no effect. A. fumigatus AlPase was totally inhibited by phenylmethanesulphonyl fluoride, antipain, chymostatin and alpha-2-macroglobulin. A. fumigatus AlPase is closely related to the A. oryzae AlPase, a serine protease of the subtilisin family, as attested by the antigen pattern seen by immunoblotting. The high collagenic activity and the ability of A. fumigatus AlPase to digest elastin could play a role in the invasion of the tissues by the fungus.
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PMID:Isolation and characterisation of an extracellular alkaline protease of Aspergillus fumigatus. 207 76

Recent clinical isolates were tested for production of some extracellular factors such as alkaline protease and elastase. They were also assayed for adhesiveness to WEHI cells. It is well known that extracellular production of substances other than toxins is related to virulence and may increase adherence. The present investigation aimed to evaluate the role of extracellular proteins in adherence. Alkaline protease production was assayed using a test performed with casein as substrate while elastase activity was investigated with the elastin-congored method. Our results demonstrated that P. aeruginosa strains which are good alkaline protease and elastase producers adher better than those showing no or low protease and elastase activity.
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PMID:Role of alkaline protease and elastase in the adherence of Pseudomonas aeruginosa to WEHI cells. 250 9

An extracellular elastase, termed Myxococcus xanthus alkaline protease 1 (MAP1), has been purified from M. xanthus DK1622 culture supernatants by a combination of ion-exchange and affinity chromatographies. It consists of a single peptide chain of 39 kDa. The elastolytic activity was totally suppressed by 10 mM 1,10-phenanthroline and the enzyme may then be classified as a metalloprotease. Its pH optimum was estimated to be 8.2 with both elastin-orcein and succinyl-Ala3 p-nitroanilide as substrates. Despite its low pI (5.2), MAP1 was adsorbed on elastin at 80%, a result which privileges hydrophobic interactions between MAP1 and elastin rather than salt bridges, as for known basic elastases. About 80% of the original amidasic and elastolytic activities were conserved after a 30-min prior incubation of the enzyme at 40 degrees C; however, 70% of the amidasic activity is measured, instead of 15% for the elastolytic activity, after 30 min at 50 degrees C. Thermal denaturation at this temperature may prevent adsorption of the enzyme on elastin without any important change of the elastase structure. MAP1 readily hydrolyzes the Gly23-Phe24 bond in the oxidized insulin B chain; the peptide bonds Ala14-Leu15, Leu15-Tyr16, Phe24-Phe25, Phe25-Tyr26 are also cleaved, suggesting a primary specificity of the enzyme for hydrophobic or aromatic residues at the first amino acid towards the C-terminus from the cleavage site (P'1 position) [Schechter, I. & Berger, A. (1967) Biochem. Biophys. Res. Commun. 27, 157-162]. This hypothesis is consistent with the fact that Ala2-Phe-Ala and Ala3-Phe-Ala are hydrolyzed even though tri-alanine to hexa-alanine oligomers are not. The evidence of an elastase with the same molecular mass and pI as MAP1 is given during fruiting body development in submerged culture of M. xanthus. The fact that aromatic amino acids have been found to be the most representative of A-signal [Kuspa, A., Plamann, L. & Kaiser, D. (1992) J. Bacteriol. 174, 3319-3326] is consistent with the hypothesis that, regarding its specificity, MAP1 is likely to play a role in development of myxobacteria.
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PMID:Purification and characterization of an alkaline elastase from Myxococcus xanthus. 805 53

The Aspergillus cell wall contains most of the antigens secreted by the fungus during its active in vitro or in vivo growth. These antigens, which bind to the IgE and IgG of allergic and aspergilloma patients or are secreted in the biological fluids of patients with invasive aspergillosis, are of primary importance in the diagnosis of aspergillosis. Located at the interface between host and pathogen cells, the fungal cell wall plays a major role during fungal invasion. It contains several surface receptors involved in adhesion of the fungus to host proteins and cells. Some of the wall antigens are also directly involved in the colonization of the host tissues by the fungus. Very few of these putative virulence factors have been purified until now. A 33-kDa alkaline protease of the subtilisin family can hydrolyze several extracellular matrix proteins such as collagen, fibrinogen, elastin. However, gene disruption experiments have shown that protease-deficient mutants are still able to infect mice. An 18-kDa antigen, which has been detected in the urine of patients with invasive aspergillosis, is present in vivo in the lung of mice infected with A. fumigatus. It has a ribonuclease activity that cleaves a single phosphodiester bond in a highly conserved region of the ribosomal RNA. Its role in the virulence of A. fumigatus has not been demonstrated until now. Biochemical and molecular characterization of the wall antigenic aggressins should be pursued.
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PMID:Cell wall antigens in Aspergillus fumigatus. 829 77

A metalloprotease (MEP) secreted by Aspergillus fumigatus was isolated from an alkaline protease-deficient mutant after the fungus was cultivated in the presence of collagen as the sole nitrogen and carbon source. The enzyme was purified 50-fold from the culture supernatant after adsorption to hydroxylapatite and carboxy-methyl-Sephadex and after gel filtration. The molecular mass was determined to be 40 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was estimated at pH 5.5 by isoelectric focusing. Reducing agents and divalent cations strongly inhibited enzyme activity, whereas nonionic detergents had no effect. A. fumigatus MEP was totally inhibited by EDTA, 1,10-phenanthroline, and phosphoramidon but not by inhibitors specific for serine, aspartate, and cysteine proteases. MEP is not able to cleave elastin and is thermosensitive. Sera from patients suffering from aspergilloma reacted with MEP in Western blotting (immunoblotting) analyses, suggesting that MEP promotes an antigenic response in these patients.
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PMID:Isolation and characterization of a secreted metalloprotease of Aspergillus fumigatus. 840 98

Little is known of the pathophysiology of invasive pulmonary aspergillosis (IPA), an opportunistic fungal infection usually caused by Aspergillus fumigatus. It has been suggested that the ability of the fungus to degrade elastin may aid its invasion and growth in lung tissue. We have described previously the construction of a strain of A. fumigatus in which the gene encoding an alkaline protease, AFAlp, had been disrupted (C.M. Tang, J. Cohen, and D.W. Holden, Mol. Microbiol. 6:1663-1671, 1992); this mutant is deficient in extracellular proteolytic and elastinolytic activity over a broad pH range. In this study, we compared the pathogenicity of this and another AFAlp disruptant with their isogenic, elastase-producing parental strains in two murine models of IPA. In both models, animals were inoculated via the respiratory tract. In the first model, the inoculum was delivered as airborne conidia and animals developed signs of respiratory distress within 2 to 4 days. In the second model, conidia were administered intranasally as a suspension and the disease developed over a 2-week period. No difference was observed between the wild-type and AFAlp disruptants in terms of mortality, and elastin breakdown was detected in lung tissue from animals inoculated with all four strains. We conclude that AFAlp is not a virulence determinant in these models of IPA.
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PMID:The alkaline protease of Aspergillus fumigatus is not a virulence determinant in two murine models of invasive pulmonary aspergillosis. 847 53

Micrococcus luteus isolated from human skin secretes an alkaline protease which degrades elastin. M. luteus protease (MLP) was produced in the late logarithmic and stationary phases of growth. MLP, purified to homogeneity by a three-step process, had a molecular mass of 32,812 Da and an isoelectric point of 9.3. MLP was active and highly stable in solution for 24 h from pH 6.0 to 10.5; it had maximal activity at temperatures between 57 and 59 degrees C. The presence of calcium in the solution was essential for enzyme activity and to prevent autolysis. Optimal activity occurred between pH 9.0 and 9.5, with 60% maximal activity from pH 6.5 to 11.0. The enzyme was inhibited by the serine enzyme inhibitors phenylmethylsulfonyl fluoride and chymostatin but not by the metalloenzyme inhibitor 1,10-phenanthroline or sulfhydryl enzyme inhibitors. Casein, bovine serum albumin, ovalbumin, beta-lactoglobulin, and elastin were digested by the protease while collagen and keratin were resistant to digestion. MLP demonstrated both esterase and amidase activity on synthetic peptide substrates. MLP preferentially cleaved the Leu(15)-Tyr(16) and Phe(24)-Phe(25) bonds of the oxidized beta-chain of insulin. Longer digests of insulin and the pattern of activity against synthetic substrates suggest that MLP has a cleavage specificity for bulky, hydrophobic, or aromatic amino acids in the P(1) or P(1)' positions. Amino acid sequences from the N-terminus and internal peptides of MLP were unique.
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PMID:Purification and characterization of a unique alkaline elastase from Micrococcus luteus. 1064 68

Pseudomonas aeruginosa secretes multiple proteases that have been implicated as virulence factors and the detection of each specific enzyme can be difficult to determine. Unlike the three Pseudomonas enzymes that have been well characterized (elastase A, elastase B, and alkaline protease), the activity of protease IV in multiple assays has yet to be described. This study defines new assays for Pseudomonas proteases and compares protease IV activity to the activities of elastase A, elastase B, and alkaline protease. Six in vitro assays were studied: zymography, elastin congo red assay, staphylolytic assay, colorimetric peptide assay, solid-phase colorimetric peptide assay, and poly-l-lysine degradation. Casein zymography distinguished protease IV from elastase B and alkaline protease, and gelatin zymography differentiated all four proteases. The elastin congo red assay detected mainly elastase B while the staphylolytic assay was specific for elastase A. Protease IV activity was assayed specifically by the colorimetric assay and two new assays, the solid-phase colorimetric assay and degradation of poly-L-lysine in the presence of EDTA. Alkaline protease could be specifically assayed by poly-L-lysine degradation in the presence of N-alpha-p-tosyl-L-lysine chloromethyl ketone. The results identified three specific assays for protease IV, a new assay specific for alkaline protease, and showed that protease IV has a distinct enzymatic specificity relative to the three other Pseudomonas proteases.
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PMID:Pseudomonas aeruginosa protease IV enzyme assays and comparison to other Pseudomonas proteases. 1123 36


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