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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytochrome P-450 isozymes, cytochrome P-450 MC1 and MC2, purified from rats treated with 3-methylcholanthrene (MC), were found by immunohistochemical staining to be strongly induced in the livers of rats treated with 3,3', 4,4'-tetrachlorobiphenyl (TCBP), while the cytochrome P-450 isozymes, PB1 and PB2, purified from the livers of rats treated with phenobarbital (PB), were shown to be induced in the livers of rats treated with 2,2', 4,4', 5,5'-hexachlorobiphenyl (HCBP). The latter compound also strongly induced NADPH-cytochrome P-450-reductase. Following induction, all 5 enzymes were located preferentially in the centrilobular and midzonal region of the liver acinus. The influence of these polychlorinated biphenyls (PCBs) on diethylnitrosamine (DEN)-initiated hepatocarcinogenesis was investigated by analyzing the evolution of adenosine triphosphatase-deficient focal lesions. Whereas DEN alone produced very few islets, the administration of either PCB congener (150 mumol/kg, i.p., once weekly over a period of 8 weeks) subsequent to DEN treatment (50 ppm in the drinking water, 10 days) strongly enhanced the number of islets as well as the relative volume of liver occupied by islet tissue. These effects were evident, both 1 and 9 weeks, after cessation of PCB treatment. Unexpectedly the less persistent PCB congener, TCBP, showed a much more potent enhancing effect after the 9 weeks recovery period than did (HCBP).
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PMID:Polychlorinated biphenyls, classified as either phenobarbital- or 3-methylcholanthrene-type inducers of cytochrome P-450, are both hepatic tumor promoters in diethylnitrosamine-initiated rats. 309 31

Renal cytochrome P-450-dependent monooxygenases metabolize arachidonic acid to products some of which affect vascular tone and (Na+,K+)ATPase activity. We measured these metabolites in spontaneously hypertensive (SHR) and control normotensive Wister-Kyoto (WKY) rats. Systolic tail blood pressure in SHR increased from 112 to 202 mm Hg and in WKY from 97 to 136 mm Hg at 5 and 20 weeks respectively. Renal cortical and outer medullary microsomes were incubated with [14C]arachidonic acid; metabolites formed via the cytochrome P-450 pathway were defined as those dependent on NADPH, inhibited by SKF-525A, and unaffected by indomethacin. The P-450-dependent metabolites were higher in SHR vs WKY at 5, 7 and 11 weeks in the cortex and at 7 and 11 weeks in the outer medulla. In the outer medulla, the formation of these metabolites peaked at 7 weeks. Using reverse-phase HPLC, the cytochrome P-450-dependent metabolites were separated into three radioactive peaks: peak I had a retention time of 17.5 min and comigrated as 11,12-dihydroxyeicosatrienoic acid standard. Peak II had a retention time of 19 min and comigrated with omega-hydroxylation compounds. Peak III had a retention time of 27 min and comigrated with 11,12-epoxyeicosatrienoic acid. In the renal cortex, peak I was higher in SHR vs WKY at 5, 7, and 9 weeks and peak III at 5, 7, 9 and 11 weeks. In the outer medulla, peak I was higher in SHR at 5 and 7 weeks, and peaks II and III at 7 weeks. Cytochrome P-450 content in the renal cortex was always higher in SHR vs WKY. We conclude that renal cytochrome P-450-dependent metabolites of arachidonic acid may participate in the circulatory changes of SHR, particularly during the developmental stage.
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PMID:Renal cytochrome P-450-dependent metabolism of arachidonic acid in spontaneously hypertensive rats. 312 63

When corneal microsomes were incubated with arachidonic acid in the presence of an NADPH-generating system, two biologically active metabolites of arachidonic acid were formed. The structure of one of the metabolites, compound C, was previously reported to be 12(R)-hydroxy-5,8,10,14-eicosatetraenoic acid and was found to be a potent inhibitor of the Na+/K+-ATPase in the cornea. The second metabolite, compound D, was found to be a potent vasodilator as well as having the property of stimulating protein influx into the aqueous humor of the eye. Following purification of compound D by thin layer chromatography and high pressure liquid chromatography, it was found to lack a UV chromophore in contrast to the previously reported cytochrome P-450-dependent metabolite. Mass spectrometric analysis using positive and negative ionization modes was carried out on derivatized compound D that had been synthesized from a mixture of labeled [( 5,6,8,9,11,12,14,15-2H8]) and unlabeled arachidonic acid incubated with corneal microsomes. The novel arachidonate metabolite had abundant fragment ions consistent with compound D being a monooxygenated derivative of arachidonic acid with a hydroxyl substituent at carbon 12 of the eicosanoid backbone; only seven deuterium atoms from [2H8]arachidonate were retained in the structure. Oxidative ozonolysis yielded a product indicating that the double bonds in metabolite D resided between carbons at positions 8 and 9 and positions 14 and 15 of the 20-carbon chain. Compound D was therefore characterized as 12-hydroxy-5,8,14-eicosatrienoic acid. Model compounds were synthesized from dimethyl malate with the hydroxy at the 12 position with both the R and S absolute configuration and with all double bonds of the cis configuration. Only the 12(R) isomer was found to be a potent vasodilator and to increase aqueous humor protein concentration, suggesting that the biologically active compound D was 12(R)-hydroxy-5,8,14-(Z,Z,Z)-eicosatrienoic acid. As this compound possesses proinflammatory properties, it may play a role in the wound-healing processes of corneal injury.
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PMID:12(R)-hydroxyeicosatrienoic acid: a vasodilator cytochrome P-450-dependent arachidonate metabolite from the bovine corneal epithelium. 314 17

Male Wistar rats fed for 60 days a glucose diet containing 17.5 mmol hexachlorobenzene/kg show a less pronounced increase in serum parameters and microsomal cytochrome P-450 concentration and a lower decrease in liver plasma membrane 5'-nucleotidase, K+, Na+- and Mg++-adenosine triphosphatase activities than the controls fed standard diet + hexachlorobenzene. Addition of 10% ethanol to the drinking water eliminates the "glucose effect". The glucose diet and ethanol exert contrasting effects on microsomal enzyme induction and liver plasma membrane damage in hexachlorobenzene intoxication.
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PMID:Interaction between glucose diet and ethanol on rat liver microsomal induction and liver plasma membrane damage in chronic hexachlorobenzene intoxication. 361 33

The effects of subcutaneous (s.c.) injections of magnesium acetate (MgAcet) on the acute toxicity of intraperitoneal (i.p.) nickelous acetate (NiAcet) were studied in rats. Male F344/NCr rats, 150-200 g body wt, received either NiAcet alone, MgAcet alone, or both. The dose of NiAcet was 115 mumol/kg body wt for the lethality and 95 mumol/kg body wt for all other tests. MgAcet was given in 400 mumol/kg body wt daily doses at -24, 0, and +24 h relative to NiAcet for the lethality study, or at -24 and 0 h for all other tests. Treatment with MgAcet increased 14-day survival of the NiAcet-injected rats (57% vs. 27%; P less than 0.02) and diminished 24-h nickel uptake in the lung (50%), liver (44%), and kidneys (30%), but not in blood, spleen, heart, or brain. MgAcet also increased (15% in 0-3 h) urinary excretion of nickel. It had no effect, however, on nickel-induced nephropathy, hyperglycemia, lipid peroxidation in liver and kidneys, and decrease in renal cytochrome P-450 content. Neither NiAcet nor MgAcet had any effect on the ATPase activity in heart and brain. These results suggest that MgAcet decreases the lethality of NiAcet by altering the pharmacokinetics of nickel(II) and not by enhancement of a pharmacodynamic tolerance to nickel(II).
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PMID:Effects of magnesium acetate on the toxicity of nickelous acetate in rats. 379 59

Nitrosamine-induced hepatocarcinogenesis has been used to investigate the regulation and expression of different drug-metabolizing enzymes in preneoplastic and neoplastic lesions in the female Wistar rat. The enzymes investigated were two phenobarbital-inducible cytochrome P-450 (cyt. P-450) isoenzymes (PB1 and PB2, mol. wt. 52 000 and 53 500, respectively), two 3-methylcholanthrene-inducible forms (MC1 and MC2, mol. wt. 54 500 and 57 000, respectively), NADPH-cytochrome P-450 reductase, the cytosolic glutathione transferases (GSTs) B and C and the microsomal epoxide hydrolase with broad substrate specificity (mEHb). Carcinogen-induced lesions were identified by use of the known markers of hepatocarcinogenesis adenosinetriphosphatase and gamma-glutamyl transpeptidase. While the GSTs and mEHb were increased in all preneoplastic and neoplastic lesions, the levels of the individual cyt. P-450 isoenzymes were characteristically different from each other. In many of the early ATPase deficient islets PB1 was elevated, whereas the content of the other cyt. P-450 forms and NADPH-cytochrome P-450 reductase was either unchanged or slightly lowered. At later stages of hepatocarcinogenesis PB1 returned to the levels of the surrounding tissue, while the other cyt. P-450 isoenzymes were decreased, the most prominent reduction being found in MC1. In neoplastic nodules all the cyt. P-450s and NADPH-cyt. P-450 reductase were diminished, some of them dramatically. These findings indicate that in spite of a common response of groups of P-450s to inducing agents, individual P-450 isoenzymes are also regulated separately. Moreover, the constant elevation of mEHb and GSTs in all lesions investigated in this study demonstrates that these enzymes, which are largely involved in deactivation, are regulated in a different fashion from the predominantly carcinogen-activating monooxygenases. The observed differences in enzyme pattern may provide a useful method for subdividing and categorizing preneoplastic and neoplastic lesions.
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PMID:Regulation and expression of four cytochrome P-450 isoenzymes, NADPH-cytochrome P-450 reductase, the glutathione transferases B and C and microsomal epoxide hydrolase in preneoplastic and neoplastic lesions in rat liver. 392 Dec 70

Plasma membranes from KB cells were isolated by the method of latex bead ingestion and were compared with those obtained by the ZnCl(2) method. Optimal conditions for bead uptake and the isolation procedure employing discontinuous sucrose gradient centrifugation are described. All steps of preparative procedure were monitored by electron microscopy and specific enzyme activities. The plasma membrane fraction obtained by both methods is characterized by the presence of the Na(+) + K(+)-activated ATPase and 5'-nucleotidase, and contains NADPH-cytochrome c reductase and cytochrome b(5). The latter two enzymes are also present in lower concentrations in the microsomal fraction. Unlike microsomes which are devoid of the Na(+) + K(+)-activated ATPase and which contain only traces of 5'-nucleotidase activity, the plasma membrane fraction contains only trace amounts of the rotenone-insensitive NADH-cytochrome c reductase but no cytochrome P-450, both of which are mainly microsomal components. Morphologically the plasma membrane fraction isolated by the latex bead method is composed of vesicles of 0.1-0.3 microm in diameter. On the basis of the biochemical and morphological criteria presented, it is concluded that the plasma membrane fraction isolated by the above methods are of high degree of purity.
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PMID:Isolation and properties of the plasma membrane of KB cells. 428 30

Rough microsomes from rat liver of both control and methylcholanthrene-treated animals were subfractionated on a discontinuous sucrose gradient into three fractions according the their sedimentation velocity. The slowly sedimenting vesicles were enriched in electron transport enzymes, while those in the pellet showed higher phosphatase and ATPase activities. Methylcholanthrene treatment introduced typical changes in enzyme composition, mainly an increase of the cytochrome P-448. The individual phospholipids exhibited an identical distribution pattern in the three subfractions and no change occurred after induction with methylcholanthrene treatment. Nearest neighbour analysis of phosphatidylethanolamine with dinitrodifluorobenzene revealed a similar pattern in the enzymatically different subfraction, that is, no cross-linking with phosphatidylserine occurred. One-third of the phosphatidylethanolamine was in monomer and dimer form and about two-thirds was protein linked. When membrane and enzyme synthesis was induced, cross-linking to proteins were substantially decreased. The experiments indicate that the phospholipids are distributed in a homogenous fashion in the lateral plane of the rough microsomal membrane and do not support the possibility that phosphatidylethanolamine is specifically associated with cytochrome P-450.
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PMID:Phospholipid and enzyme arrangements of rat liver rough microsomal subfractions from control and methylcholanthrene-treated animals. 628 90

Significant changes are observed in wet weight, microsomal protein content and enzymes of purified rough and smooth microsomes of liver during postnatal development and ageing of female Wistar rats. Protein content of total microsomes increases up to 15 days of age and remains steady during subsequent development, unlike that of rough and smooth microsomes which shows changes throughout the same period. Activities of cytochrome P-450, cytochrome b5 and NADPH-cytochrome c reductase increase during the period of maturation and decline during senescence. The decrease during senescence is at different rates in the two microsomal fractions. Microsomal glucose-6-phosphatase, but not adenosine triphosphatase, shows a similar increase during development and decrease during senescence.
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PMID:Changes in enzymes of hepatic rough and smooth microsomes during postnatal development and ageing of rats. 631 Feb 80

We studied arachidonic acid (AA) metabolism by a cell suspension containing principally cells of the thick ascending limb of the loop of Henle (TALH) obtained from the inner stripe of the outer medulla of the rabbit kidney. Based on comparison of specific activities of enzymes before and after separation, alkaline phosphatase, Na+-K+-adenosine triphosphatase, as well as Tamm-Horsfall glycoprotein and electron microscopic appearance, 80% of these cells were estimated to be TALH in origin. TALH cells had low activity of cyclooxygenase and did not show evidence of lipoxygenase activity. However, they selectively converted exogenous AA to oxygenated metabolites by a cytochrome P-450 related mechanism. AA metabolites were produced in large amounts (30-40% conversion of [14C]AA, 1 to 5 micrograms/mg of protein/30 min) and were increased 5-fold after separation of TALH cells from a suspension of outer medullary cells, suggesting that TALH cells synthesized these metabolites. Induction of cytochrome P-450 by pretreatment of rabbits with beta-naphthoflavone and 3-methylcholanthrene increased formation of the AA metabolites by almost 2-fold in the separated cells and correlated with cytochrome P-450 content of the renal outer medulla. Additionally, SKF 525A and carbon monoxide inhibited product formation in these renomedullary cells, supporting a role for a cytochrome P-450-like monooxygenase in TALH cell function.
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PMID:Arachidonic acid metabolism in a cell suspension isolated from rabbit renal outer medulla. 643 72


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