Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of fixation with various concentrations of glutaraldehyde or formaldehyde, acetone or ethanol, and freeze-drying on 5 phosphatases of Eimeria tenella and chick kidney cell cultures were demonstrated in situ. Gultaraldehyde inactivated the phosphatases more than did the formaldehyde, but the effect of the combination of the 2 (Karnovsky's fixative) was greater than that of either glutaraldehyde or formaldehyde alone. The higher the concentration of aldehyde and the longer the duration of exposure, the greater the inactivation. The order of sensitivity to aldehyde fixation of the enzymes tested was glucose-6-phosphatase greater than thiamine pyrophosphatase greater than 5'-nucleotidase greater than adenosine triphosphatase greater than acid phosphatase. Cytologic detail was preserved more efficiently with glutaraldehyde than with formaldehyde. Optimal preservation of enzyme activity for cytochemistry was with 2% glutaraldehyde for 30 min or 2% formaldehyde for 1 hr for G-6-Pase, TPPase, and 5'-nucleotidase, and with 2% glutaraldehyde or 2% formaldehyde for 2 hr with ATPase and AcPase. Quenching with subsequent fixation in cold acetone or ethanol resulted in complete inactivation of G-6-Pase, TPPase, and 5'-nucleotidase; although cells fixed in this manner yielded large amounts of reaction product for ATPase and AcPase, the distribution was diffuse, and some of it appeared to be artifactual. Quenching with subsequent freeze-drying was unsatisfactory because nearly all of the cell layers rolled off the cover glasses.
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PMID:Effect of fixation on demonstration of phosphatases of Eimeria tenella grown in chick kidney cell cultures. 6 Dec 71

Recent experiments have described the presence of cytochrome P-450 and certain P-450 isozymes in the plasma membrane of rat liver. Experiments were carried out to evaluate whether cytochrome P-450IIE1 was present in the plasma membrane fraction of livers from control rats and rats treated with 4-methylpyrazole, which induces this isozyme. Using immunofluorescence, fluorescence was detected at the surface of intact hepatocytes that were initially incubated with anti-P-450IIE1 IgG, but not preimmune IgG, followed by incubating with goat antirabbit IgG conjugated with either fluorescein or rhodamine. The fluorescence appeared to be uniformly distributed across the entire surface. Intense intracellular staining could be observed when the hepatocytes were permeabilized by acetone treatment. Similar results were obtained with control hepatocytes; however, the fluorescence intensity was considerably less than that shown by the induced hepatocytes. Hepatocytes isolated from the pericentral zone of the liver acinus displayed more intense fluorescence at the surface than did hepatocytes from the periportal zone. Purified plasma membranes oxidized dimethylnitrosamine to formaldehyde at rates that were 14% to 30% that of the microsomes, which exceeds the 3% contamination of the plasma membranes by microsomes as assessed by glucose-6-phosphatase activity. Immunoblots of the plasma membranes revealed the presence of a single band, whose intensity of staining was 14% to 26% that of the microsomes. Oxidation of dimethylnitrosamine and immunoblot intensity were about twofold greater with plasma membrane fractions from 4-methylpyrazole-treated rats than controls. These results suggest the presence of inducible, functionally active P-450IIE1 in the plasma membrane, which may be of toxicological significance in view of the preferential metabolism of a variety of hepatotoxins and carcinogens and the elevated production of reactive oxygen intermediates by this isozyme.
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PMID:Presence of functionally active cytochrome P-450IIE1 in the plasma membrane of rat hepatocytes. 154 34

Previous studies have demonstrated that the hepatotoxin carbon tetrachloride rapidly promotes lipid peroxidation and inhibits microsomal calcium sequestration, microsomal glucose-6-phosphatase activity and cytochrome P-450. Due to its profound effects on lipid peroxidation, we have examined the oral administration of 2.5 ml/kg carbon tetrachloride on the urinary excretion of the lipid metabolites formaldehyde, malondialdehyde, acetaldehyde and acetone. Urine samples were collected up to 48 h after treatment. The urinary metabolites were identified and quantitated by gas chromatography-mass spectrometry and high-pressure liquid chromatography. Time-dependent increases in the urinary excretion of the four metabolites were observed after carbon tetrachloride administration. At 48 h after treatment, the increases in the excretion of malondialdehyde, formaldehyde, acetaldehyde and acetone were approximately 55, 78, 57 and 268%, respectively, relative to control values. The data were expressed in nanomoles per kilogram body weight per 4.5 h. The results clearly demonstrate that carbon tetrachloride increases the urinary excretion of four lipid metabolites which may serve as noninvasive biomarkers of xenobiotic-induced lipid peroxidation.
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PMID:Carbon-tetrachloride-induced urinary excretion of formaldehyde, malondialdehyde, acetaldehyde and acetone in rats. 841 71

The pregnant rats were treated with formaldehyde (0.5 mg/kg daily per os) during whole period of pregnancy. The activity of cytochrome-c-oxidase, malate dehydrogenase, nucleotidase, glucose-6-phosphatase, beta-glucuronidase, N-acetyl-beta-glucosaminidase, beta-galactosidase, H(+)-ATPase, glutamate dehydrogenase, NAD- and NADP-isocitrate dehydrogenase, fructose-bisphosphate aldolase, glucose-6-phosphate dehydrogenase and content of protein in liver celts of offsprings (newborns, 2 weeks age and 2 months age) were studied. It was shown differences in development enzyme systems of control and experimental animals during ontogenesis.
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PMID:[Experimental study of the effect of formaldehyde during embryogenesis on the activity of rat liver enzyme systems in ontogenesis]. 913 53