Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 role of alkaline protease in the development of myocardial lesions in myopathic hamsters was studied. There was abnormal elevation of alkaline protease in the myopathic heart at 1 month of age, preceding the development of cardiac lesions. In vivo treatments of verapamil were carried out in 1-month-old myopathic animals for 30 days. Results indicated that the drug treatment was effective in preventing the occurrence of the severe myocardial lesions found in the untreated animals at 2 months of age. Reduced lesion development was associated concomitantly with lowered levels of alkaline protease activity. Withdrawal of drug treatment caused the return of severe lesions and high levels of alkaline protease. The study of the alkaline protease activity in the skeletal muscle of the myopathic hamster also showed a parallel relationship between the enzyme levels and severity of lesions. The results are discussed in light of possible involvement of a serine protease and a Ca2+-activated protease in producing the cardiac lesions.
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PMID:The role of alkaline protease in the development of cardiac lesions in myopathic hamsters: effect of verapamil treatment. 639 77

Saccharomycopsis lipolytica CX161-1B, a strain suitable for genetic studies, when grown at neutral pH produced a single alkaline extracellular protease, lower levels of acid extracellular protease(s) and no neutral extracellular protease. The alkaline protease was purified to homogeneity (as determined by polyacrylamide gel electrophoresis) by ultrafiltration, gel filtration and DEAE-cellulose chromatography. The molecular weight of the enzyme was estimated by gel filtration to be 27000-30000, and the isoelectric point was pH 5.7. The purified enzyme had an alkaline pH optimum (pH 9-10). It was completely inhibited by phenylmethylsulphonyl fluoride, reversibly inhibited by EDTA, partially inhibited by o-phenanthroline, and not inhibited by dithiothreitol, N-ethylmaleimide or 4-hydroxymercuribenzoic acid, indicating that it is a serine protease. The content of sulphur amino acids was determined, and the purified protease contained no more than 1.8% carbohydrate as determined by the phenol-sulphuric acid method. The N-terminal amino acid sequence (25 residues) was determined; the N-terminal amino acid was alanine.
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PMID:Alkaline extracellular protease produced by Saccharomycopsis lipolytica CX161-1B. 675 31

Proteolytic enzyme activities were measured in skeletal muscle of Sprague-Dawley rats with streptozotocin-induced diabetes [tail vein injection of streptozotocin (100 mg/kg), under ether anesthesia]. Assay of rat muscle homogenates from diabetic rats revealed a significant increase in alkaline serine protease activity as compared to untreated control rats and diabetic rats given insulin. There were no significant changes in lysosomal cathepsin activities in diabetic muscle as compared to controls. Gel studies of myofibrils isolated from the three groups of rats, subjected to autolysis, revealed that the serine protease had copurified with the myofibrils. Treatment of rats with compound 48/80, which degranulates mast cells, abolished the alkaline protease activity. There was no serine protease activity associated with the myofibrils isolated from compound 48/80-treated rats. Results from this study indicate that serine proteases are not involved in muscle protein breakdown in diabetes and are of mast cell origin.
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PMID:Muscle proteolytic enzyme activities in diabetic rats. 703 84

Thermostable alkaline protease from an alkaliphilic thermophile Bacillus sp. B18' was purified by using DEAE- and CM-Toyopearl 650M column chromatographies. Molecular weights of the enzyme determined by SDS-PAGE and gel filtration were 30,000 and 28,000, respectively. The optimum pH and temperature toward the hydrolysis of casein were pH 12-13 and 85 degrees C, both of which are higher than those of a mesophilic alkaline protease from an alkaliphile, Bacillus sp. B21-2. The enzyme was stable at pH 5.0-12.0 and about 60% of the initial enzymatic activity was retained after a 60 min incubation period at pH 10.0 and 70 degrees C. Thermostability of the enzyme was enhanced by Ca2+. The enzyme activity was inhibited by DFP, suggesting that the enzyme is a serine protease. The NH2-terminal amino acid is Gln, which is that of many subtilisin-type proteases. The 20 residues of the NH2-terminal amino acid sequence have a comparative high homology with those of other alkaline proteases from alkaliphiles (40-50%), especially thermostable alkaline protease from Bacillus sp. No. AH-101 (95%) and Thermoactinomyces sp. HS682 (95%).
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PMID:Purification and properties of the highly thermostable alkaline protease from an alkaliphilic and thermophilic Bacillus sp. 776 36

The 20 S proteasome, found in eukaryotes and in the archaebacterium Thermoplasma acidophilum, forms the proteolytic core of the 26 S proteasome which is the central protease of the non-lysosomal protein degradation pathway. Inhibitor studies have indicated that the 20 S proteasome may be an unusual type of cysteine or serine protease and a recent study of the Thermoplasma beta subunit has indicated that it carries the proteolytic activity. We have attempted to obtain information on the nature of the active site by mutating the only cysteine, both histidines and two completely conserved aspartates in the archaebacterial complex as well as all serines of the beta subunit, without decreasing the catalytic activity of the enzyme to any significant extent. Indeed, mutation of the conserved aspartate in the beta subunit increased the activity of the proteasome threefold. We conclude that the proteasome is not a cysteine or serine protease.
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PMID:The proteasome from Thermoplasma acidophilum is neither a cysteine nor a serine protease. 786 93

An extracellular proteasome-like (EP) structure has been isolated from serum-free media conditioned by C6 astrocytoma cells. EP has a native molecular mass of 1000 kDa and is composed of three subunits, two isoelectric variants at 70 kDa and one at 65 kDa. The extracellular proteasome degraded collagen IV, alpha-casein, beta-insulin, and certain synthetic peptide substrates. A 68-kDa type IV collagenase, identified as the activated form of gelatinase A, was also isolated from this medium. The type IV collagenase activity of the proteasome was sensitive to serine protease inhibitors, while the 68-kDa collagenase IV represented the matrix metalloprotease gelatinase A. The general protease activity of the proteasome was sensitive to metalloprotease inhibitors. Western blot analysis indicates a sequence relationship between the 68-kDa type IV collagenase and either one or both of the 70-kDa isoelectric variants of the proteasome; however, the two enzymes appear to be distinct functionally. Comparison with known proteasomes indicates that EP represents a novel proteasome. The complexity of degradative enzymes in the extracellular microenvironment implies that complete inhibition of tumor growth requires at least a combination of serine and metalloprotease inhibitors.
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PMID:An extracellular proteasome-like structure from C6 astrocytoma cells with serine collagenase IV activity and metallo-dependent activity on alpha-casein and beta-insulin. 787 29

Rational shift of the optimum pH toward alkalinity and enhancement of thermostability were investigated by using a thermostable extremely alkaline protease (optimum pH, 12 to 13) from the alkaliphilic and thermophilic Bacillus sp. strain B18'. The protease gene (aprM) was cloned, and the sequence analysis revealed an open reading frame of 361 amino acids that was composed of a putative signal sequence (24 amino acids), a prosequence (69 amino acids), and a mature enzyme (268 amino acids) (molecular weight, 27,664). The amino acid sequence of this protease was compared with those of other serine proteases. A direct correlation of higher optimum pH with an increase in the number of arginine residues was observed. An even more thermostable mutant enzyme was created by introducing a point mutation. When the position of the beta-turn, Thr-203, was replaced by Pro, the residual activity of this mutant enzyme at 80 degrees C for 30 min was higher than that of the wild-type enzyme (50% versus 10%). The specific activity of this mutant enzyme at 70 degrees C was 105% of that of the wild-type enzyme under nondenaturation condition. These data suggest that the higher content of Arg residues favors the alkalinity of the serine protease and that introduction of a Pro residue into the beta-turn structure stabilizes the enzyme.
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PMID:Stabilization and rational design of serine protease AprM under highly alkaline and high-temperature conditions. 798 36

A 32-kDa nonglycosylated alkaline protease (EC 3.4.1.14) with elastolytic activity, secreted by the opportunistic pathogen Aspergillus fumigatus ATCC 42202, is suggested to be a virulence factor of this fungus. The enzyme is a serine protease of the subtilisin family, and its cDNA nucleotide sequence has recently been reported. We have cloned the cDNA encoding the mature protease into a high-level Escherichia coli expression plasmid and produced the recombinant protease as a fusion protein with a six-adjacent-histidine affinity tag at the carboxy terminus. Subsequently, the recombinant protease was purified to homogeneity, with affinity chromatography yielding 30 to 40 mg of recombinant protease per liter of E. coli culture. Refolded recombinant protease, in comparison with native protease, demonstrated weak enzymatic activity but similar immunochemical characteristics as analyzed by antigen-specific enzyme-linked immunosorbent assay (ELISA), competition ELISA, and immunoblotting assays. To assess the allergenic potential of the protease, sera from patients with allergic bronchopulmonary aspergillosis and sera from healthy control individuals were analyzed by ELISA and immunoblotting techniques. Sera from patients with allergic bronchopulmonary aspergillosis did not have protease-specific immunoglobulin E (IgE) antibodies and, remarkably, did not show significantly elevated protease-specific IgG antibody levels compared with those in sera from healthy control individuals. This suggests that the alkaline protease from A. fumigatus does not elicit IgE antibodies and has weak immunogenicity, a property which may explain fungus persistence in allergic individuals.
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PMID:Recombinant expression and antigenic properties of a 32-kilodalton extracellular alkaline protease, representing a possible virulence factor from Aspergillus fumigatus. 811 66

Aspergillus fumigatus produced a 33-kDa serine protease (ALP) in vitro and in vivo. In vitro, this alkaline protease was secreted when the fungus was cultivated in the absence of protein, if the pH of the medium remained close to neutrality. Western blotting and immunoelectronmicroscopy studies showed that ALP was localised in the wall of the fungus and was degraded after secretion in the culture medium under conditions of low pH. Although present in the lung during infection, ALP did not appear to be diagnostically useful and was different from the precipitating chymotrypsin antigen used in the diagnosis of aspergilloma.
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PMID:Identification of the 33-kDa alkaline protease of Aspergillus fumigatus in vitro and in vivo. 824 56

A number of isolates of Aspergillus fumigatus obtained from the hospital environment produced extracellular elastolytic activity. This activity was found to be catalyzed by a single 33-kDa protein which was purified and characterized to be a serine protease. A. fumigatus, when grown on the insoluble structural material obtained from murine and bovine lung, produced the same extracellular 33-kDa elastolytic protease, indicating that this enzyme is likely to be produced when the organism infects the lung. Polymerase chain reaction with an oligonucleotide primer based on the N-terminal amino acid sequence of the elastolytic enzyme yielded a cDNA which was cloned and sequenced. The active serine motif showed more similarity to subtilisin than to mammalian elastase. The amino acid sequence showed 80% identity to the alkaline protease from Aspergillus oryzae. Screening of hospital isolates of Aspergillus flavus showed great variation in the production of elastolytic activity and a much lower level of activity than that produced by A. fumigatus. The elastolytic protease from A. flavus was shown to be a serine protease susceptible to modification and inactivation by active serine and histidine-directed reagents. This protease cross-reacted with the antibodies prepared against the elastolytic protease from A. fumigatus. Immunogold localization of the elastolytic enzyme showed that A. fumigatus germinating and penetrating into the lungs of neutropenic mice secreted the elastolytic protease. An elastase-deficient mutant generated from a highly virulent isolate of A. fumigatus caused drastically reduced mortality when nasally introduced into the lung of neutropenic mice. All of the evidence suggests that extracellular elastolytic protease is a significant virulence factor in invasive aspergillosis.
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PMID:Evidence for possible involvement of an elastolytic serine protease in aspergillosis. 850 Aug 76


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