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)

Protease activity was detected in membranes of human bovine erythrocytes prepared by the conventional procedures which include washing and removal of the "buffy layer". The enzyme was extracted by 0.75 M KCNS or (NH4)2SO4 and was activated by 0.4 to 0.5 M of the same salts. Colored, particulate hide powder-azure, membrane fractions and soluble proteins such as hemoglobin, casein or albumin were susceptible to hydrolysis by the membraneous protease. Partial purification of the enzyme was accomplished through disc-gel electrophoresis on polyacrylamide in the presence of 0.25% positively charged detergents like cetyltrimethylammonium bromide. An alkaline protease (pH 7.4) with properties similar to those of the erythrocyte enzyme was found in leucocytes. The similarity between the properties of the leucocytic and erythrocytic proteases and the correlation of the activity in erythrocyte membranes with content of white cells in these preparations, suggest that enzymatic activities in the contaminating leucocytes are responsible for the activity of membraneous proteases in erythrocytes.
Biochim Biophys Acta 1975 Dec 16
PMID:Membrane-bound enzymes. III. Protease activity in leucocytes in relation to erythrocyte membranes. 0 92

The sequence of the amino-terminal 349 residues of rabbit muscle glycogen phosphorylase (EC 2.4.1.1) has been determined. Limited proteolysis of native phosphorylase b (841 residues, subunit molecular weight 97 412) by subtilisin BPN', Streptomyces alkaline protease, or elastase yielded two large segments (light and heavy). The light segment isolated from the subtilisin digest was cleaved at methionyl bonds with cyanogen bromide to yield eight major fragments and two minor overlapping fragments. The alignment of the major fragments was obtained by analysis of the two minor fragments, of five tryptic peptides containing methionine and of one large fragment generated by cleavage of an aspartylproline bond. Analysis of two cyanogen bromide fragments (CB14 and CB17) isolated from the intact molecule identified the sites susceptible to limited proteolysis and the overlap between the light and the heavy segments. Serine-14 and tyrosine-155 were identified as the residues involved in the covalent and allosteric controls of the enzyme, respectively. Residues 108 and 142 were identified as the cysteine residues reported to be involved in the aggregation of subunits.
Biochemistry 1978 Dec 26
PMID:Sequence of the amino-terminal 349 residues of rabbit muscle glycogen phosphorylase including the sites of covalent and allosteric control. 72 24

Due to the loss of enzymatic activity as a function of time, an alkaline protease, selected for the continuous preparation of protein hydrolysates (J. Boudrant and C. Cheftel, Biotechnol. Bioeng., 18,1735, 1976), was chemically stabilized by a simple treatment with glutaraldehyde. Two fractions, soluble and insoluble, were obtained. The activities of these two fractions were measured with casein and N-benzoyl-L-arginine ethyl ester (BAEE) as a function of glutaraldehyde concentration used. It was noted that the insoluble fraction was practically inactive with the first substrate and that the heat stability of the soluble form was likewise enhanced. Molecular weights of these two forms were unchanged, but the uv-spectrum of the soluble form was modified. From amino acid analysis, it appears that this treatment mainly provokes a decrease in lysine content.
Biotechnol Bioeng 1976 Dec
PMID:Continuous Proteolysis with a stabilized stabilized protease. I. Chemical stabilization of an alkaline protease. 82 55

Western blot analysis, using a polyclonal antibody to the 240-kDa endogenous inhibitor of the 20 S proteasome, revealed that the inhibitor is a component of the 26 S complex. Although isolated inhibitor displayed a single 40-kDa band on SDS-PAGE, the antibody detected a 55-kDa component in the 26 S proteasome complex. Ubiquitin polyclonal antibody recognized the same 55-kDa component but did not react with free 40-kDa inhibitor subunit. Addition of purified 40-kDa inhibitor to a ubiquitin ligating system also generated the 55-kDa species. In crude erythrocyte extracts, most of the inhibitor migrated at 55 kDa in the presence of ATP but shifted to 40 kDa in the absence of ATP, consistent with removal of ubiquitin. It is suggested that ubiquitination of the inhibitor may be involved in regulating assembly and/or activity of the 26 S proteasome complex.
Biochemistry 1992 Dec 08
PMID:Ubiquitinated proteasome inhibitor is a component of the 26 S proteasome complex. 133 90

Ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis, is the most rapidly turned over mammalian enzyme. We have shown that its degradation is accelerated by ODC antizyme, an inhibitory protein induced by polyamines. This is a new type of enzyme regulation and may be a model for selective protein degradation. Here we report the identification of the protease responsible for ODC degradation. Using a cell-free degradation system, we demonstrate that immunodepletion of proteasomes from cell extracts causes almost complete loss of ATP- and antizyme-dependent degradation of ODC. In addition, purified 26S proteasome complex, but not the 20S proteasome, catalyses ODC degradation in the absence of ubiquitin. These results strongly suggest that the 26S proteasome, widely viewed as specific for ubiquitin-conjugated proteins, is the main enzyme responsible for ODC degradation. The 26S proteasome may therefore have a second role in ubiquitin-independent proteolysis.
Nature 1992 Dec 10
PMID:Ornithine decarboxylase is degraded by the 26S proteasome without ubiquitination. 133 32

In eukaryotes, the ubiquitin-dependent protoelytic pathway is one of the major routes by which intracellular proteins are selectively destroyed. Recent work has shown that conjugation of ubiquitin to substrate proteins is mediated by a remarkably diverse array of enzymes. Proteolytic targeting may also be regulated at steps between ubiquitination of the substrate and its degradation to peptides by the multisubunit 26S protease. The complexity of the ubiquitin system suggests a central role for protein turnover in eukaryotic cell regulation.
Curr Opin Cell Biol 1992 Dec
PMID:Ubiquitin and intracellular protein degradation. 133 69

During the course of the transformation of 1,3-dichloro-2-propanol (DCP) into (R)-3-chloro-1,2-propanediol [(R)-MCP] with the cell extract of Corynebacterium sp. strain N-1074, epichlorohydrin (ECH) was transiently formed. The cell extract was fractionated into two DCP-dechlorinating activities (fractions Ia and Ib) and two ECH-hydrolyzing activities (fractions IIa and IIb) by TSKgel DEAE-5PW column chromatography. Fractions Ia and Ib catalyzed the interconversion of DCP to ECH, and fractions IIa and IIb catalyzed the transformation of ECH into MCP. Fractions Ia and IIa showed only low enantioselectivity for each reaction, whereas fractions Ib and IIb exhibited considerable enantioselectivity, yielding R-rich ECH and MCP, respectively. Enzymes Ia and Ib were isolated from fractions Ia and Ib, respectively. Enzyme Ia had a molecular mass of about 108 kDa and consisted of four subunits identical in molecular mass (about 28 kDa). Enzyme Ib was a protein of 115 kDa, composed of two different polypeptides (about 35 and 32 kDa). The specific activity of enzyme Ib for DCP was about 30-fold higher than that of enzyme Ia. Both enzymes catalyzed the transformation of several halohydrins into the corresponding epoxides with liberation of halides and its reverse reaction. Their substrate specificities and immunological properties differed from each other. Enzyme Ia seemed to be halohydrin hydrogen-halide-lyase which was already purified from Escherichia coli carrying a gene from Corynebacterium sp. strain N-1074.
J Bacteriol 1992 Dec
PMID:Resolution and some properties of enzymes involved in enantioselective transformation of 1,3-dichloro-2-propanol to (R)-3-chloro-1,2-propanediol by Corynebacterium sp. strain N-1074. 144 32

Proteasomes are intracellular protein complexes displaying multiproteolytic activities. These complexes have been implicated in the antigen degradation process that generates peptides associated with the major histocompatibility complex (MHC) class-I molecule. RING10 and RING12 are genes encoded by the class-II region of the human MHC that have sequence homology to proteasome-encoding genes. We have identified a yeast gene, called PRG1, that encodes a protein predicted to contain 55.6% sequence identity to 80% of the RING10 gene product. Genomic disruption of PRG1 revealed that it is essential for yeast cell growth. These data strongly indicate that the antigen-processing system present in vertebrates evolved from a basic cellular process present in all organisms.
Gene 1992 Dec 01
PMID:A homolog of the proteasome-related RING10 gene is essential for yeast cell growth. 145 31

Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).
Poult Sci 1992 Dec
PMID:Correlation of biological value of feed phosphates with their solubility in water, dilute hydrogen chloride, dilute citric acid, and neutral ammonium citrate. 147 May 90

The latent form of multicatalytic proteinase complex (MCP) was purified to homogeneity from ovine skeletal muscle. The MCP ran as a single band (M(r) 600,000) on nondenaturing polyacrylamide gel (PAGE) and dissociated to a number of subunits (M(r) 21,000 to 31,000) under denaturing and reducing conditions (SDS-PAGE). The proteinase complex was activated reversibly by heating at 60 degrees C and in the presence of SDS. Maximum activation (18-fold) was observed after 2 min at 60 degrees C and there was rapid inactivation beyond 2 min. Maximum proteolytic activity (12.8-fold) occurred in the presence of .25 mM SDS and diminished rapidly at higher SDS concentrations. The MCP was maximally active at pH 7.5 to 8.0 and 45 degrees C using radiolabeled alpha-casein. These and other results (e.g., proteinase inhibitor profiling) indicate that ovine skeletal muscle does indeed contain MCP and that its biochemical properties are the same as MCP isolated from other sources. By using [14C]-casein as a substrate, the specific activities (milligrams of protein degraded/milligrams of proteinase) for mu-, m-calpain, and MCP were 44.0, 59.7, and 2.0, respectively. Purified ovine myofibrils were incubated with mu-calpain or MCP. Classical effects of calpains, which include degradation of Z-disks, titin, desmin, troponin-T, and troponin-I and removal of alpha-actinin, were observed. However, only troponin-C and myosin light chains-2 and -3 were degraded by MCP. Morphologically, MCP had no detectable effect on myofibrils. Results suggest that MCP is not involved in the initial steps of myofibril disassembly. However, its involvement in the degradation of myofilaments remains to be determined.
J Anim Sci 1992 Dec
PMID:Ovine skeletal muscle multicatalytic proteinase complex (proteasome): purification, characterization, and comparison of its effects on myofibrils with mu-calpains. 147 9


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