Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the intermediate-term effects of three consecutive evenings of moderate ethanol ingestion (0.75 g/kg body weight each evening) on activity values for alkaline phosphatase, gamma-glutamyltransferase, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in sera of nine apparently healthy young adults. We define "intermediate-term" effects as those occurring between 10 h and 100 h after completion of the ethanol consumption schedule. The most pronounced changes in enzyme activity for the group of volunteers were: gamma-glutamyltransferase, +25% at 60 h after ethanol ingestion; alanine aminotransferase, +12% at 60 h after ethanol; and aspartate aminotransferase,--12% at 60 h after ethanol. All three enzymes exhibited similar time courses, i.e., mean peak activity changes were observed at 60 h, and all three mean enzyme activity values returned to near baseline by 100 h. The possible explanations for the observed changes and the clinical significance are discussed.
 ...
PMID:The effects of ethanol (0.75 g/kg body weight) on the activities of selected enzymes in sera of healthy young adults: 1. Intermediate-term effects. 1 40

Mercurochrome strongly inhibits aspartate transaminase and 2,3-dicarboxyethylated aspartate transaminase. The native enzyme exhibits a biphasic time-course of inactivation by mercurochrome with second-order rate constants 1.62 x 10(4) M-1 - min-1 and 2.15 x 10(3) M-1 - min-1, whereas the modified enzyme is inactivated more slowly (second-order rate constant 6.1 x 10(2) M-1 - min-1) under the same conditions. The inhibitor inactivates native and modified enzyme in the absence as well as in the presence of substrates. Mercurochrome-transaminase interaction is accompanied by a red shift in the absorption maximum of the fluorochrome of about 10 nm. Difference spectra of the mercurochrome-enzyme system versus mercurochrome, compared with analogous spectra of mercurochrome-ethanol, revealed that the spectral shifts recorded during mercurochrome-transaminase interaction are similar to those that occur when mercurochrome is dissolved in non-polar solvents. Studies of mercurochrome complexes with native or modified transaminase, isolated by chromatography on Sephadex G-25, revealed that native transaminase is able to conjugate with four mercurochrome molecules per molecule, but the modified enzyme is able to conjugate with only two mercurochrome molecules per molecule.
 ...
PMID:Interaction of aspartate aminotransferase with mercurochrome. Relationship of an exposed thiol group of the enzyme to the active centre. 7 75

The serum concentration of ethanol and the activities of aspartate aminotransferase, alanine aminotransferase and gamma-glutamyltransferase (GT) in 40 male chronic alcoholics were determined on admission to hospital. The serum activities of the enzymes were highest in patients with established alcoholism for less than 5 years. The serum concentration of ethanol, however, was lowest among these patients and gradually increased with the duration of alcoholism. No correlation was found between the serum ethanol level and the activity of any of the enzymes. The duration of the current debauch, which was shortest in cases of long-standing alcoholism, showed a positive correlation with the S-GT activity.
 ...
PMID:Serum ethanol, hepatic enzymes and length of debauch in chronic alcoholics. 43 73

Pregnant albino rats were placed on a complete liquid diet (Ensure) containing either 9% ethanol or an isocaloric amount of sucrose between the third and twentieth day of gestation. The pups born to these rats were sacrificed either day 11 or day 14 postnatum and morphometrical, histological and biochemical analyses were done on their cerebellums and cerebrums. Pups that were exposed to ethanol in utero had significantly smaller body weights, cerebrums and cerebellums than pair-fed controls. The cerebellar mass was reduced by 10% and the cerebral weight by 3% in the pups exposed to alcohol when body weights were normalized to that of pair-fed controls. Cerebellar aspartyl aminotransferase (EC 2.6.1.1) activity was reduced at day 11 and 14 in ethanol treated pups compared with controls. Serum T4 levels were also reduced in the ethanol treated group. Histological analyses revealed that the external granule cell (EGC) layer of ethanol treated pups was significantly thicker at 11 and 14 days postnatum than that of pair-fed control pups. Cerebellar ornithine decarboxylase (ODC, EC 4.1.1.17) activity was higher at day 11 in the ethanol treated pups than in controls. The reduced mass, AAT activity, T4 serum levels and the increased thickness of the ECG layer indicate a delayed or impeded maturation of cerebellum in ethanol treated pups. These data are considered from the viewpoint that ethanol, other drugs such as methadone and prenatal stress (malnutrition) may cause delayed cerebellar maturation by reducing serum T4 levels in the early postnatal period (day 5-14).
 ...
PMID:Impeded cerebellar development and reduced serum thyroxine levels associated with fetal alcohol intoxication. 49 36

Eighty-eight patients with a non-alcoholic and 105 patients with an alcoholic liver disease were warned against alcohol consumption. On three consecutive ambulatory visits, serum ethanol was measured and compared with patients' admission of alcohol intake. None in the non-alcoholic group had a positive serum ethanol test, whereas 60 samples from 40 patients with alcoholic liver disease were positive. The serum ethanol values were higher in women than in men. Continuation of drinking was unrelated to sex, age, or type of alcoholic liver disease. Twenty-seven of the 40 patients with ethanol in serum denied alcohol consumption. The reliability of the patients was unrelated to sex, age, or type of alcoholic liver disease. Serum ethanol was more valuable than aspartate aminotransferase, alkaline phosphatase, bilirubin, and coagulation factors in pointing out the patients who continued drinking.
 ...
PMID:Serum ethanol estimations in the control of alcohol abstinence in patients with liver disease. 53 8

The hypothesis that mictochondrial damage is a significant factor in the pathogenesis of alcoholic liver disease (ALD) was investigated by enzymic analysis of mitochondrial fractions isolated from needle biopsy specimens from control patients, patients with fatty liver due to chronic alcoholism, and from patients with other forms of liver disease. Enzymes associated with the inner and outer mitochondrial membranes showed normal levels in ALD. Enzymes associated with the mitochondrial matrix, glutamate dehydrogenase, malate dehydrogenase and aspartate aminotransferase showed significantly raised levels in ALD, but the levels in patients with non-alcoholic liver disease was normal. In addition, analysis of the mitochondria by sucrose density gradient centrifugation revealed no differences between control tissue and liver from patients with alcoholic liver disease. These results do not indicate that there is significant mitochondrial damage in ALD. The raised mitochondrial matrix enzymes may represent an adaptive response to the ethanol load.
 ...
PMID:Mitochondrial enzyme activities in liver biopsies from patients with alcoholic liver disease. 65 61

In isolated hepatocytes from normal fed rats, the subcellular distribution of malate, citrate, 2-oxoglutarate, glutamate, aspartate, oxaloacetate, acetyl-CoA and CoASH has been determined by a modified digitonin method. Incubation with various substrates (lactate, pyruvate, alanine, oleate, oleate plus lactate, ethanol and aspartate) markedly changed the total cellular amounts of metabolites, but their distribution between the cytosolic and mitochondrial compartments was kept fairly constant. In the presence of lactate, pyruvate or alanine, about 90% of cellular aspartate, malate and oxaloacetate, and 50% of citrate was located in the cytosol. The changes in acetyl-CoA in the cytosol were opposite to those in the mitochondrial space, the sum of both remaining nearly constant. The mitochondrial acetyl-CoA/CoASH ratio ranged from 0.3-0.9 and was positively correlated with the rate of ketone body formation. The mitochondrial/cytosolic (m/c) concentration gradients for malate, citrate, 2-oxoglutarate, glutamate, aspartate, oxaloacetate, acetyl-CoA and CoASH averaged from hepatocytes under different substrate conditions were determined to be 1.0, 8.8, 1.6, 2.2, 0.5, 0.7, 13 and 40, respectively. From the distribution of citrate, a pH difference of 0.3 across the inner mitochondrial membrane was calculated, yet lower values resulted from the m/c gradients of 2-oxoglutarate, glutamate and malate. The mass action ratios for citrate synthase and mitochondrial aspartate aminotransferase have been calculated from the metabolite concentrations measured in the mitochondrial pellet fraction. A comparison with the respective equilibrium constants indicates that in intact hepatocytes, neither enzyme maintains its reactants at equilibrium. On the assumption that mitochondrial malate dehydrogenase and 3-hydroxybutyrate dehydrogenase operate near equilibrium, the concentration of free oxaloacetate appears to be 0.3-2 micron, depending on the substrate used. Plotting the calculated free mitochondrial oxaloacetate concentration against the citrate concentration measured in the mitochondrial pellet yielded a hyperbolic saturation curve, from which an apparent Km of citrate synthase for oxaloacetate in the intact cells of 2 micron can be derived, which is comparable to the value determined with purified rat liver citrate synthase. The results are discussed with respect to the supply of substrates and effectors of anion carriers and of key enzymes of the tricarboxylic acid cycle and fatty acid biosynthesis.
 ...
PMID:Distribution of metabolites between the cytosolic and mitochondrial compartments of hepatocytes isolated from fed rats. 68 Jun 39

Male rats provided with a 5 or 15% (v/v) ethanol solution as the sole source of fluid consumed ethanol at a rate of 11.4 or 24.9% of total calories (4.2 or 8.3 g/kg daily). After ethanol consumption lasting 1, 2 and 3 weeks the hepatotoxicity of CCl4 (0.1 ml/kg i.p.) was elevated by determination of serum activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase ( GPT), sorbitol dehydrogenase (SDH) and histological investigations. Carbon tetrachloride (CCl4)-induced liver damage was significantly greater in rats provided with ethanol than in the tap-water consuming controls. This potentiation of CCl4 hepatotoxicicty was fully developed already after a 1-week exposition to ethanol and was greater in the 15% than in the 5% ethanol group. Ethanol alone did not influence serum enzyme activities but increased microsomal aniline hydroxylation. There was, however, no clear-cut parallelism between potentiation of CCl4 hepatotoxicity and activation of aniline hydroxylation.
 ...
PMID:Increased carbon tetrachloride hepatotoxicity after low-level ethanol consumption. 70

The purification procedure reported includes fractionation of water extract from chicken hearts with ammonium sulfate, fractional precipitation with ethanol, chromatography on Whatman CM-52 cellulose and crystallization. Specific activity of the pure crystalline enzyme was 234 micromoles.min-1.mg-1, as determined in the coupled assay with malate dehydrogenase (pH 7.5; 25 degrees). The amino acid composition of the enzyme was determined and the circular dichroism spectrum was recorded in the 200-250 nm range. The spectrum shows two negative bands with extrema at 208 and 220 nm. From the circular dichroism data it is estimated that aspartate transaminase contains approximately 40% alpha-helix and 10% beta-structure.
 ...
PMID:[Improved procedure for purification of aspartate transaminase from chicken heart cytosol. Characterization of the enzyme]. 73 31

1. Isolated hepatocytes were used to establish the reasons for the accumulation of aspartate, previously observed when the isolated rat liver was perfused with ethanol in the presence of alanine or ammonium lactate. 2. The isolated cells did not form aspartate when incubated with alanine and ethanol, but much aspartate was formed on incubation with ammonium lactate and ethanol. 3. Urea was the main nitrogenous product on incubation with alanine, in contrast with the perfused liver, where major quantities of NH4+ are also formed. When the formation of urea was nullified by the addition of urease, alanine plus ethanol caused aspartate formation, indicating that aspartate formation depends on the presence of critical concentrations of NH4+. 4. The accumulated aspartate was present in the cytosol. Ethanol halved the content of 2-oxoglutarate in the cytosol and more than trebled that of glutamate in the mitochondria. 5. The findings support the assumption that 2-oxoglutarate formed by the mitochondrial aspartate aminotransferase is not translocated to the cytosol in the presence of ethanol and NH4+, because it is rapidly converted into glutamate, the dehydrogenation of ethanol providing the required NADH. Aspartate, however, is translocated to the cytosol and accumulates there because of the lack of stoicheiometric amounts of oxoglutarate.
 ...
PMID:The accumulation of aspartate in the presence of ethanol in rat liver. 120 Oct 7


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