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

---

Query: EC:3.4.25.1 (proteasome)
28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The accumulation of alpha-synuclein, ubiquitin and other proteins in Lewy bodies in degenerating dopaminergic neurones in substantia nigra in idiopathic Parkinson's disease (PD) suggest that inhibition of normal/abnormal protein degradation may contribute to neuronal death. We now show for the first time that the chymotrypsin- (39%), trypsin- (42%) and postacidic-like (33%) hydrolysing activities of 20/26S proteasome are impaired in substantia nigra in PD. Proteasome inhibition does not appear to result from drug treatment since high concentrations of L-3,4-dihydroxyphenylalanine had no effect on enzymatic activity in vitro. These observations provide the first direct evidence that inhibition of the ubiquitin-proteasome pathway leading to altered protein handling and Lewy body formation may be responsible for degeneration of the nigrostriatal pathway in idiopathic PD.
...
PMID:Proteasomal function is impaired in substantia nigra in Parkinson's disease. 1113 60

Ascidian eggs are surrounded by a noncellular layer and two cellular layers, which are penetrated by sperm. Three sperm surface proteases are essential for fertilization of eggs from the stolidobranch ascidian Halocynthia: spermosin, acrosin, and the proteasome. In the phlebobranch Ciona, a chymotrypsin-like protease and the proteasome are essential in fertilization. Sperm from the phlebobranch ascidians Phallusia mammillata, Ascidia (=Phallusia) nigra, and Ascidia columbiana, all express spermosin, acrosin, and the proteasomal chymotrypsin activities on their surfaces. Chymostatin blocks cleavage in phlebobranchs, but inhibitors of spermosin and acrosin only delay it by several minutes. Protease inhibitors have little effect upon sperm binding in Phallusia but strongly affect the rate of sperm passage through the vitelline coat. Peptide substrates and inhibitors to spermosin and acrosin cause a significant decline in the number of eggs undergoing pre-meiotic contractions at 3 min after fertilization. Thus while chymotrypsin activity is essential for penetration of the vitelline coat, spermosin and acrosin both function to increase the rate of fertilization. A crucial step in the divergence of the phlebobranchs and stolidobranchs may have been the conversion of spermosin and acrosin to essential proteases in the stolidobranchs, or, perhaps, their essential function was lost in the evolution of phlebobranchs. Aplousobranch ascidians are all colonial with very small zooids. Sperm from Aplidium californicum, Aplidium solidum (Polyclinidae), and Distaplia occidentalis (Holozoidae) have acrosin and chymotrypsin activities but lack spermosin activity. This enzyme is also missing from sperm of colonial phlebobranch and stolidobranch ascidians, suggesting that spermosin is not necessary for small zooids with internal fertilization.
...
PMID:Sperm surface proteases in ascidian fertilization. 1175 25

Alcohol can be considered as a nutritional toxin when ingested in excess amounts and leads to skeletal muscle myopathy. We hypothesized that altered protease activities contribute to this phenomenon, and that differential effects on protease activities may occur when: (1) rats at different stages in their development are administered alcohol in vivo; (2) acute ethanol treatment is superimposed on chronic alcohol-feeding in vivo; and (3) muscles are exposed to alcohol and acetaldehyde in vivo and in vitro. In acute studies, rats weighing approximately 0.1 kg (designated immature) or approximately 0.25 kg (designated mature) body weight (BW) were dosed acutely with alcohol (75 mmol/kg BW; intraperitoneal [IP], 2.5 hours prior to killing) or identically treated with 0.15 mol/L NaCl as controls. In chronic studies, rats (approximately 0.1 kg BW) were fed between 1 to 6 weeks, with 35% of dietary energy as ethanol, controls were identically treated with isocaloric glucose. Other studies included administration of cyanamide (aldehyde dehydrogenase inhibitor) in vivo or addition of alcohol and acetaldehyde to muscle preparations in vitro. At the end of the treatments, cytoplasmic (alanyl-, arginyl-, leucyl-, prolyl-, tripeptidyl-aminopeptidase and dipeptidyl aminopeptidase IV), lysosomal (cathepsins B, D, H, and L, dipeptidyl aminopeptidase I and II), proteasomal (chymotrypsin-, trypsin-like, and peptidylglutamyl peptide hydrolase activities) and Ca(2+)-activated (micro- and milli-calpain and calpastatin) activities were assayed. (1) Acute alcohol dosage in mature rats reduced the activities of alanyl-, arginyl- and leucyl aminopeptidase (cytoplasmic), dipeptidyl aminopeptidase II (lysosomal), and the chymotrypsin- and trypsin-like activities (proteosomal). No significant effects were observed in similarly treated immature rats. (2) Alcohol feeding in immature rats did not alter the activities of any of the enzymes assayed at 6 weeks. (3) In immature rats, activities of cathepsins B and D were not overtly affected at either 3, 7, 14, 28, or 42 days. (4) Superimposing acute (2.5 hours) on chronic (4 weeks feeding of immature rats) ethanol treatment (ie, chronic + acute) reduced the activities of cytoplasmic proline aminopeptidase and the chymotrypsin- and trypsin-like activities of the proteasome. (5) Cathepsin D activities were reduced in muscle homogenates upon addition of alcohol and acetaldehyde in vitro. (6) Cyanamide pretreatment in combination with alcohol dosage in immature rats did not significantly alter any protease activities. The data suggests that mature rats are more sensitive to the effects of acute alcohol on muscle proteases. Protease activities may be affected by acetaldehyde or alcohol levels as indicated by in vitro experiments. The reduction in muscle protease activities in chronic + acute alcohol superimposition may reflect the effect of acute alcohol dosage alone. Overall, there was no evidence for increased protease activity in any of the experimental situations.
...
PMID:Effect of acute and chronic alcohol treatment and their superimposition on lysosomal, cytoplasmic, and proteosomal protease activities in rat skeletal muscle in vivo. 1178 79

We have isolated four related compounds named phepropeptins A, B, C, and D, as inhibitors of proteasome proposed to regulate many cellular functions. From an NMR analysis, the phepropeptins appeared as cyclic hexapeptides, differing in the two residues of the constituent amino acids from one another, with four conserved amino acid moieties. Based on an amino acid analysis, we synthesized two possible cyclic peptides to phepropeptin B that differ in the configurations. A comparison of the properties between the natural and synthesized compounds revealed that the structure of phepropeptin B was cyclo(-L-Leu-D-Phe-L-Pro-L-Phe-D-Leu-L-Val-). The phepropeptins showed inhibition to the proteasomal chymotrypsin-like activity but not to alpha-chymotrypsin.
...
PMID:Isolation and structural determination of phepropeptins A, B, C, and D, new proteasome inhibitors, produced by Streptomyces sp. 1182 28

A series of 36 linear and cyclic beta- and gamma-peptides consisting of as few as two, and as many as 15 residues, was offered as substrates to 15 commercially available proteases of bacterial, fungal, and eukaryotic origin, including a beta-lactamase and amidases, as well as most vigorous, nonspecific proteases, such as the 20S proteasome from human erythrocytes. For comparison, an alpha-eicosapeptide and standard substrates of the proteolytic enzymes were included in the investigation. Under conditions of complete cleavage of the alpha-peptide within 15 min the beta- and gamma-peptides were stable for at least 48 h. Inhibition studies with seven beta- and gamma-peptides and alpha-chymotrypsin show that the residual enzyme activity toward succinyl-Ala-Ala-Pro-Phe-p-nitroanilide is unchanged within experimental error after incubation for 15 min with the peptide analogues. Thus, beta- and gamma-peptides with proteinogenic side chains, that is, consisting of the singly or doubly homologated natural alpha-amino acids (one or two CH(2) groups inserted in the backbone of each residue), are completely stable to common proteases, without inhibiting their normal activity (as demonstrated for alpha-chymotrypsin). This proteolytic stability of peptides built of homologated amino acids is a prerequisite for their potential use as drugs.
...
PMID:The outstanding biological stability of beta- and gamma-peptides toward proteolytic enzymes: an in vitro investigation with fifteen peptidases. 1182 76

PA700, the 19 S regulatory complex of the 26 S proteasome, plays a central role in the recognition and efficient degradation of misfolded proteins. PA700 promotes degradation by recruiting proteasomal substrates utilizing polyubiquitin chains and chaperone-like binding activities and by opening the access to the core of the 20 S proteasome to promote degradation. Here we provide evidence that PA700 in addition to binding misfolded protein substrates also acts to remodel their conformation prior to proteolysis. Scrambled RNase A (scRNase A), a misfolded protein, only slowly refolds spontaneously into an active form because of the rate-limiting unfolding of misfolded disulfide isomers. Notably, PA700 accelerates the rate of reactivation of scRNase A, consistent with its ability to increase the exposure of these disulfide bonds to the solvent. In this regard, PA700 also exposes otherwise buried sites to digestion by exogenous chymotrypsin in a polyubiquitinated enzymatically active substrate, pentaubiquitinated dihydrofolate reductase, Ub(5)DHFR. The dihydrofolate reductase ligand methotrexate counters the ability of PA700 to promote digestion by chymotrypsin. Together, these results indicate that in addition to increasing substrate affinity and opening the access channel to the catalytic sites, PA700 activates proteasomal degradation by remodeling the conformation of protein substrates.
...
PMID:Conformational remodeling of proteasomal substrates by PA700, the 19 S regulatory complex of the 26 S proteasome. 1201 Oct 44

Chemotherapy has cachectic effects, but it is unknown whether cytostatic agents alter skeletal muscle proteolysis. We hypothesized that chemotherapy-induced alterations in protein synthesis should result in the increased incidence of abnormal proteins, which in turn should stimulate ubiquitin-proteasome-dependent proteolysis. The effects of the nitrosourea cystemustine were investigated in skeletal muscles from both healthy and colon 26 adenocarcinoma-bearing mice, an appropriate model for testing the impact of cytostatic agents. Muscle wasting was seen in both groups of mice 4 days after a single cystemustine injection, and the drug further increased the loss of muscle proteins already apparent in tumor-bearing animals. Cystemustine cured the tumor-bearing mice with 100% efficacy. Surprisingly, within 11 days of treatment, rates of muscle proteolysis progressively decreased below basal levels observed in healthy control mice and contributed to the cessation of muscle wasting. Proteasome-dependent proteolysis was inhibited by mechanisms that include reduced mRNA levels for 20S and 26S proteasome subunits, decreased protein levels of 20S proteasome subunits and the S14 non-ATPase subunit of the 26S proteasome, and impaired chymotrypsin- and trypsin-like activities of the enzyme. A combination of cisplatin and ifosfamide, two drugs that are widely used in the treatment of cancer patients, also depressed the expression of proteasomal subunits in muscles from rats bearing the MatB adenocarcinoma below basal levels. Thus, a down-regulation of ubiquitin-proteasome-dependent proteolysis is observed with various cytostatic agents and contributes to reverse the chemotherapy-induced muscle wasting.
...
PMID:Chemotherapy inhibits skeletal muscle ubiquitin-proteasome-dependent proteolysis. 1201 53

The cytoplasmic trafficking of the prototype strain of minute virus of mice (MVMp) was investigated by analyzing and quantifying the effect of drugs that reduce or abolish specific cellular functions on the accumulation of viral macromolecules. With this strategy, it was found that a low endosomal pH is required for the infection, since bafilomycin A(1) and chloroquine, two pH-interfering drugs, were similarly active against MVMp. Disruption of the endosomal network by brefeldin A interfered with MVMp infection, indicating that viral particles are routed farther than the early endocytic compartment. Pulse experiments with endosome-interfering drugs showed that the bulk of MVMp particles remained in the endosomal compartment for several hours before its release to the cytosol. Drugs that block the activity of the proteasome by different mechanisms, such as MG132, lactacystin, and epoxomicin, all strongly blocked MVMp infection. Pulse experiments with the proteasome inhibitor MG132 indicated that MVMp interacts with cellular proteasomes after endosomal escape. The chymotrypsin-like but not the trypsin-like activity of the proteasome is required for the infection, since the chymotrypsin inhibitors N-tosyl-L-phenylalanine chloromethyl ketone and aclarubicin were both effective in blocking MVMp infection. However, the trypsin inhibitor Nalpha-p-tosyl-L-lysine chloromethyl ketone had no effect. These results suggest that the ubiquitin-proteasome pathway plays an essential role in the MVMp life cycle, probably assisting at the stages of capsid disassembly and/or nuclear translocation.
...
PMID:Cytoplasmic trafficking of minute virus of mice: low-pH requirement, routing to late endosomes, and proteasome interaction. 1243 89

Novel N-arylsulfonyldipeptidyl aldehyde derivatives were prepared by DMSO oxidation from the corresponding dipeptide alcohol, and their potencies as calpain inhibitors were evaluated in vitro. Among them, N-(4-fluorophenylsulfonyl)-l-valyl-l-leucinal (8, SJA6017) potently inhibited calpains. 8 also inhibited cathepsin B and L but did not inhibit other cysteine proteases (interleukin 1beta-converting enzyme), serine proteases (trypsin, chymotrypsin, thrombin, factor VIIa, factor Xa), or proteasome. Preliminary cytotoxicity studies of 8 exhibited a relatively safe profile.
...
PMID:Structure-activity relationship study and drug profile of N-(4-fluorophenylsulfonyl)-L-valyl-L-leucinal (SJA6017) as a potent calpain inhibitor. 1259 66

A series of new 7-substituted-4-chloro-3-alkoxy isocoumarin derivatives were synthesized and evaluated as inhibitors of representative classes of proteases: serine protease (alpha-chymotrypsin, trypsin), cysteine protease (Caspase-3), and aspartyl protease (HIV-protease), 20S proteasome and also as inhibitors of amyloid peptide gamma-secretase-mediated production. Protease inhibition selectivity is directly related to the structure of the substituent at the 7-position of the isocoumarin nucleus. 7-Nitro-isocoumarin derivatives (4c, 4d, 4f) are potent alpha-chymotrypsin inhibitors but slightly active or inactive on HIV-protease, as well as on cysteine protease. In contrast, only derivatives bearing a free amino (5d, 5f) or a substituted amino group (6f) at the 7-position of the isocoumarin nucleus, were found weakly active or inactive on alpha-chymotrypsin, trypsin, Caspase-3 and HIV-protease, but prevent gamma-secretase-mediated production of Abeta 40/42 amyloid peptides, which is known to be involved in Alzheimer's disease. Moreover, the most active compounds on beta-amyloid peptide production [JLK6 (5d), JLK2 (5f) and JLK7 (6f)] show only weak or moderate inhibitory activity on the 20S proteasome. The obtained results suggest that the described new isocoumarin analogues could be of interest, since compounds like JLK6 (5d), JLK2 (5f) and JLK7 (6f) can be considered as possible hits for the development of new agents directed towards Alzheimer's disease.
...
PMID:Synthesis of new 3-alkoxy-7-amino-4-chloro-isocoumarin derivatives as new beta-amyloid peptide production inhibitors and their activities on various classes of protease. 1281 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---