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)

Component polypeptides of both the bovine lens and pituitary multicatalytic proteinase complexes demonstrate different immunoreactivities with a polyclonal antiserum raised against the purified pituitary enzyme. Four (Mr 24000, 26000, 34000 and 38000) of eight bands that have been resolved by SDS/polyacrylamide-gel electrophoresis are stained in immunoblot experiments. Monospecific antibodies obtained from this antiserum by affinity purification from the 38000- and 34000-Mr bands of the lens enzyme bound equally well to either band, but showed little or no binding to the 26000- and 24000-Mr bands upon immunoblotting. Antibody affinity-purified from the 24000-Mr band showed comparable binding to the 24000-, 34000- or 38000-Mr band. One explanation of these results is that the 24000-Mr polypeptide is derived from the higher-Mr polypeptide(s) and has lost some of the common immunodeterminants.
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PMID:Common epitopes of bovine lens multicatalytic-proteinase-complex subunits. 246 61

The multicatalytic proteinase, ingensin, was purified to homogeneity from chicken liver. rRNA-degrading activity was co-eluted with the purified multicatalytic proteinase from a TSK-3000SW column. This RNA-degrading activity was inactivated by heat treatment and the addition of a low concentration of SDS. Therefore, the RNA-degrading activity co-eluted with the multicatalytic proteinase was not due to contamination by low-molecular-mass RNases. These results strongly suggest that this RNA-degrading activity was tightly associated with the multicatalytic proteinase, ingensin.
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PMID:RNA degrading activity is tightly associated with the multicatalytic proteinase, ingensin. 247 78

Freshly isolated monocytes in suspension express 2000 to 4000 high affinity receptors for IFN-gamma. Because monocytes change phenotypically as they migrate out of the circulation and adhere to extracellular matrix, modulation of the expression of IFN-gamma receptors may occur. In order to determine if adherence alone modulates the receptor for IFN-gamma, we have studied receptor expression in adherent human peripheral blood monocytes. Elutriation-purified monocytes were allowed to adhere to polystyrene overnight at 37 degrees C. These cells now expressed 1 to 2 x 10(5) low affinity (Ka = 10(8) liters/M) receptors for [125I]rIFN-gamma. Binding to this receptor was specific and saturable. The expression of these receptors occurred rapidly (within 3 h) after adherence and was not inhibited by cycloheximide treatment. Binding to the receptor was abrogated by treating cells with trypsin, but was enhanced after treatment with alkaline protease or proteinase K. mAb against the high affinity receptor did not block binding to the low affinity receptor on adherent cells. The low affinity receptor transduced a signal to the cell as measured by the IFN-gamma-induced enhancement in FcR for human IgG1. The structure of the receptor on adherent cells was investigated by chemical cross-linking techniques. A receptor-[125I]rIFN-gamma complex was observed by SDS-PAGE to have a Mr of 180,000 to 200,000. Reduction of this complex with 2-ME resulted in the loss of the high Mr complex and the appearance of a doublet of lower Mr of 68,000 and 82,000. In contrast, cross-linking of monocytes in suspension yielded a complex of 110,000 to 120,000 Mr, which was unchanged upon reduction. Upon adherence, human monocytes express large numbers of a novel receptor for rIFN-gamma which is capable of stimulating the cell. This receptor appears to be composed of at least two components which are disulfide linked and structurally differs from the high affinity receptor on nonadherent monocytes.
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PMID:Characterization of a novel low affinity receptor for IFN-gamma on adherent human monocytes by radioligand binding studies and chemical cross-linking. 252 81

Chymotrypsin-like activity of the multicatalytic proteinase (MCP) purified from eggs of the ascidian Halocynthia roretzi was activated by the addition of SDS. Complete activation was achieved simultaneously at the time of SDS addition, and this activity decreased as a function of time. Autonomous fluorescence of MCP also increased rapidly at the time of SDS addition and then decreased at a rate that depended on the SDS concentration. The decrease of autonomous fluorescence induced by SDS preceded that of the activity. These results suggest that a rapid conformational change of MCP induced by SDS results in the enhancement of chymotrypsin-like activity, followed by the decrease of this activity because of the lability of the activated conformation.
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PMID:Sodium dodecyl sulfate-induced conformational and enzymatic changes of multicatalytic proteinase. 275 56

Monoclonal antibodies (MoAbs) produced against SDS-disrupted bovine papillomavirus type 1 (BPV-1) were used to identify the product of the L1 open reading frame (ORF) of BPV-1. MoAbs were tested in ELISA with purified BPV-1 major capsid protein, fusion proteins from two constructions of the BPV-1 L1 ORF, and one construction of the L2 ORF. All MoAbs were reactive with purified MCP and both L1 fusion proteins. No MoAbs were identified that were reactive with the L2 fusion protein. Polyclonal antisera raised against SDS-disrupted BPV-1 were immunoreactive with both L1 and the L2 fusion proteins. These data show that the L1 ORF of BPV-1 encodes, at least in part, the MCP of BPV-1. Further, it has been shown that the L1 encodes the papillomavirus (PV) genus-specific epitope, PV broadly cross-reactive epitope, BPV minimally cross-reactive epitope, and a BPV-1 type-specific epitope.
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PMID:Identification of the bovine papillomavirus L1 gene product using monoclonal antibodies. 284 6

Purified Pseudomonas aeruginosa elastase cleaved human type III and IV collagens with the formation of specific cleavage products. Furthermore, type I collagen appeared to be slowly cleaved by both P. aeruginosa elastase and alkaline protease. These cleavage fragments from type III and IV collagens were separated from the intact collagen chains by SDS polyacrylamide gradient gel electrophoresis run under reducing conditions, and they were detected by their characteristic Coomassie blue staining pattern. The results of these studies suggest that the pathogenesis of tissue invasion and hemorrhagic tissue necrosis observed in P. aeruginosa infections may be related to the degradation of these collagen types by bacterial extracellular proteases.
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PMID:Specific cleavage of human type III and IV collagens by Pseudomonas aeruginosa elastase. 307 27

Lipoxygenase purified from rabbit reticulocyte lysate has a molecular mass of 68 kDa on SDS gel and a pI of 5.97. Lipoxygenase is inhibited by nordihydroguaiaretic acid (NDGA), 3-amino-1-(m-(trifluoromethyl)phenyl)-2-pyrazoline (BW755C), 5,8,11,14-eicosatetraynoic acid (ETYA), salicylhydroxamate (SHAM) or hemin. Metal ions or nucleotides do not affect its activity. The addition of certain of these inhibitors to the reticulocyte extract also inhibited the ATP-dependent proteolysis of casein, one of the distinct characteristics of reticulocytes. No clear correlation between lipoxygenase activity and ATP-dependent proteolysis could be detected. Hemin and NDGA inhibited both processes, but the concentrations necessary for inhibition were quite different. SHAM completely inhibited lipoxygenase, but not proteolysis. o-Phenanthroline inhibited ATP-dependent proteolysis, but had no effect on lipoxygenase activity. We have also purified a high-molecular-mass protease, ingensin, from reticulocyte extract. This protease accounted for more than 90% of the casein-degrading activity in reticulocyte extract. NDGA inhibited ingensin at the same concentrations required for inhibition of ATP-dependent proteolysis. These results suggest that lipoxygenase is not indispensable for the ATP-dependent proteolysis and the novel high-molecular-mass protease, ingensin, may be involved in the process.
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PMID:Reticulocyte lipoxygenase, ingensin, and ATP-dependent proteolysis. 308 25

We investigated and characterized the ATP-dependent protease in human erythroleukemia, K562 cells. The succinyl-leucyl-leucyl-valyl-tyrosine-methylcoumarinamide hydrolytic activity in a K562 lysate at pH 9 rose more than 10-fold with the addition of 1 mM ATP. The effect of ATP on the protease activity was dose-dependent and inhibited by the addition of ADP. This activity was not inhibited by EDTA, L-3-carboxy-trans-2,3-epoxypropionyl-leucylamide-(4-guanidin o)butane or leupeptin, but was strongly inhibited by chymostatin and diisopropylfluorophosphate. The protease activity was eluted just after the void volume from a G3000SW HPLC column. The above results suggest that this protease is identical to the high-molecular-mass protease, ingensin, previously reported by us. The ATP-dependent increase in the protease activity was due to prevention of the inactivation of the protease by ATP, and not to activation of the protease itself in the reaction mixture at 37 degrees C. The depressed succinyl-leucyl-leucyl-valyl-tyrosine-methylcoumarinamide hydrolytic activity in the ATP-depleted lysate was restored to the same level by the detergent, SDS. Therefore, we conclude that the inactivation of ingensin occurring on preincubation is not irreversible.
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PMID:An ATP-dependent protease and ingensin, the multicatalytic proteinase, in K562 cells. 314 70

A high molecular weight, fatty acid- and SDS-sensitive protease named ingensin was purified from rat brain in this study. The enzyme purified from rat brain has the same biochemical properties as those purified from other tissues, e.g., porcine skeletal muscle, human placenta, and rat liver in our laboratory, and rat skeletal muscle and bovine pituitary gland in other laboratories, independently. Immunoblot bands were detected in the same positions as those in the case of ingensin from rat liver. In addition, its topographical distribution was studied in rat brain and muscle by means of the immunohistochemical method. The cytoplasm of motor neurons of the spinal cord, pyramidal cells, and granular cells of the hippocampus, Purkinje cells, and glial cells were stained. Axons were stained. The cytoplasm of muscle was also stained, especially that of type 2 fibers.
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PMID:Localization of ingensin in rat central nervous system and skeletal muscle. 318 9

Candida olea 148 secreted a single acid protease when cultured at acidic pH. In unbuffered medium, the culture pH eventually became alkaline and a single alkaline protease was produced. This was the only proteolytic enzyme produced when the organism was grown in buffered medium at alkaline pH. Both proteolytic enzymes were purified to homogeneity (as assessed by SDS-PAGE). The Mr of the acid protease was 30900, the isoelectric point 4.5; optimum activity against haemoglobin was at 42 degrees C and pH 3.3. This enzyme was inactivated at temperatures above 46 degrees C and was inhibited by either pepstatin and diazoacetyl-norleucine methyl ester but was insensitive to inhibition by either 1,2-epoxy-3-(p-nitrophenoxy)-propane or compounds known to inhibit serine, thiol or metallo proteases. The acid protease contained 11% carbohydrate. The alkaline protease had an Mr of 23400 and isoelectric point of 5.4. The activity of this enzyme using azocoll as substrate above 42 degrees C and was inhibited by phenylmethyl-sulphonyl fluoride and irreversible inactivated by EDTA. The enzyme was also partially inhibited by DTT but was insensitive to either pepstatin or p-chloromercuribenzoic acid.
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PMID:Extracellular acid and alkaline proteases from Candida olea. 331 74


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