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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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).
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PMID:Impeded cerebellar development and reduced serum thyroxine levels associated with fetal alcohol intoxication. 49 36

In order to assess the extent to which metabolism within the sheep placenta may influence the transfer of metabolites between mother and foetus at different stages of gestation the activities of enzymes concerned with some aspects of carbohydrate, amino acid and keton body metabolism were determined in placental cotyledons resected from ewes during the last three months of pregnancy. The activities of pyruvate kinase (EC 2.7.1.40), lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37), ATP citrate (pro-3S)-lyase (EC 4.1.3.8), citrate (si)-synthase (EC 4.1.3.7), acetyl-CoA synthetase (EC 6.2.1.1), acetyl-CoA acetyltransferase (EC 2.3.1.9) and 3-keto acid CoA-transferase (EC 2.8.3.5) per gram wet weight cotyledon do not change during the period studied. The activities of alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1), isocitrate dehydrogenase (NADP+) (EC 1.1.1.42), ornithine-oxoacid aminotransferase (EC 2.6.1.13) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) show an increase in activity between the third and fourth months of pregnancy whilst the activities of arginase (EC 3.5.3.1) and possibly pyruvate carboxylase (EC 6.4.1.1) show an increase in activity between the fourth and final months of pregnancy. Ornithine decarboxylase (EC 4.1.1.17) activity declines to one tenth of its activity during this later period. The absence of detectable activities of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) and ornithine carbamoyltransferase (EC 2.1.3.3) indicate that gluconeogenesis and urea synthesis from ammonia do not occur in the sheep placenta. It appears that the ability of the placenta to metabolise several substrates is achieved by the time the placenta reaches its maximum size at approximately 90 days.
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PMID:Enzyme activities in the sheep placenta during the last three months of pregnancy. 84 73

After a chloroform intraperitoneal injection, lactate dehydrogenase, alanine aminotransferase and particularly aspartate aminotransferase serum activities are much more raised in deficient animals. Liver ornithine decarboxylase (ODC) activity normally decreases in rats between the 4th. and the 7th. month after the weaning. In vitamin A deficient animals, basal values of the enzyme activity are lower and the decrease is deeper. But even at month 7, liver sustains a partial capacity of ODC recovery if retinol is fed during 15 days. Chloroform administration strongly enhances liver ODC activity in normal rats. In the deficiency, stimulation is lower in absolute value but relatively higher if referred to basal level. After retinol refeeding, chloroform stimulates enzyme activity to nearly normal values. Vitamin A deficiency impairs obviously liver ODC activity and its response to chloroform stimulation in rats, but the stroke is at least partially reversible in our conditions. Moreover, deficient animals maintain a non negligible capacity of ODC response under chloroform stimulation.
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PMID:[Toxicity of chloroform and vitamin A status in the rat]. 145 50

The irreversible ornithine decarboxylase and extrahepatic arginase inhibitors (+)-S-2-amino-5-iodoacetamidopentanoic acid (2-AIPA) and (+)-S-2-amino-6-iodoacetamidohexanoic acid (2-AIHA) were evaluated. The LD50 tests were made in rats and mice using both compounds. Rats and mice were treated with either 2-AIPA or 2-AIHA i.p. for a period of 180 days. The treated animals showed a decrease of total serum proteins and increased ALT and AST levels. CK was also modified but inversely related to dose. Protection tests were carried out using L5178Y mouse lymphosarcoma. The mean survival time for each treated group was calculated and the percentage T/C was determined. For 2-AIPA it was 170 and for 2-AIHA it was 210 at 15 mg/kg.
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PMID:Antitumor effect and toxicity of two new active-site-directed irreversible ornithine decarboxylase and extrahepatic arginase inhibitors. 148 67

The primary structure of tyrosine aminotransferase, as deduced from the nucleotide sequence of complementary DNA, was confirmed by fast atom bombardment mass spectrometry of tryptic peptides derived from the purified protein. Limited digestion of the native enzyme with trypsin released an acetylated, amino-terminal peptide; the new amino terminus in the modified enzyme was Val65. Endogenous proteases generated a chromatographically separable form of tyrosine aminotransferase that began at Lys35. Neither trypsin nor the other proteases altered the catalytic activity of tyrosine aminotransferase. Reduction of the holoenzyme with sodium borohydride yielded a major tryptic peptide containing phosphopyridoxamine bound to lysine 280, which probably functions in transamination. The carboxyl terminus of tyrosine aminotransferase contains features that typify proteins with short half-lives; it includes two negatively charged, hydrophilic segments that are enriched for glutamyl residues and are similar to a PEST region in ornithine decarboxylase (Rogers, S., Wells, R., and Rechsteiner, M. (1986) Science 234, 364-368). Tyrosine aminotransferase belongs to a superfamily of enzymes which includes aspartate aminotransferase and can be aligned so that many invariant, functional residues coincide. Like the isoenzymes of aspartate aminotransferase, tyrosine aminotransferase may contain two domains, with a central, catalytic core, and a small domain made up of both amino- and carboxyl-terminal components. We speculate that the exposed small domain may confer the unusually rapid degradative rate that characterizes this enzyme.
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PMID:The structure of tyrosine aminotransferase. Evidence for domains involved in catalysis and enzyme turnover. 256 40

Rats were injected intraperitoneally with CCl4 (2.5 ml/kg body wt.) and the hepatotoxicity was compared with that of rats receiving the same dose of CCl4 and an intraperitoneal injection of fructose 1,6-bisphosphate (2 g/kg body wt.). A 50-70% decrease in plasma aspartate aminotransferase and alanine aminotransferase activities was observed in the latter treatment, indicating a protective role of the sugar bisphosphate in CCl4 hepatotoxicity. The protection was accompanied by elevated hepatic activities of ornithine decarboxylase at 2, 6 and 24 h, S-adenosylmethionine decarboxylase at 6 h, and spermidine N1-acetyltransferase at 2 h. The increase in the enzymes involved in polyamine metabolism was shown in our previous work [Rao, Young & Mehendale (1989) J. Biochem. Toxicol. 4, 55-63] to correlate with increased polyamine synthesis or interconversion, which was related to the extent of hepatocellular regeneration. The hepatic contents of fructose 1,6-bisphosphate and ATP significantly decreased after CCl4 treatment, and administration of the sugar bisphosphate increased hepatic ATP. Fructose 1,6-bisphosphate, an intermediary metabolite of the glycolytic pathway, may decrease CCl4 toxicity by increasing the ATP in the hepatocytes. The ATP generated is useful for hepatocellular regeneration and tissue repair, events which enable the liver to overcome CCl4 injury.
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PMID:Protective role of fructose 1,6-bisphosphate during CCl4 hepatotoxicity in rats. 259 Jan 62

1-Aminooxy-3-aminopropane was shown to be a potent competitive inhibitor (Ki = 3.2 nM) of homogenous mouse kidney ornithine decarboxylase, a potent irreversible inhibitor (Ki = 50 microM) of homogeneous liver adenosylmethionine decarboxylase and a potent competitive (Ki = 2.3 microM) of homogeneous bovine brain spermidine synthase. It did not inhibit homogeneous bovine brain spermine synthase and it did not serve as a substrate for spermidine synthase. The compound did not inhibit tyrosine aminotransferase, alanine aminotransferase or aspartate aminotransferase, which are pyridoxal phosphate-containing enzymes like ornithine decarboxylase. The inactivation of adenosylmethionine decarboxylase was partially prevented by pyruvate, which is the coenzyme of adenosylmethionine decarboxylase, and by the substrate, adenosylmethionine. 1-Aminooxy-3-aminopropane at 0.5 mM concentration inhibited the growth of HL-60 promyelocytic leukemia cells and this inhibition was prevented by spermidine but not by putrescine.
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PMID:1-Aminooxy-3-aminopropane, a new and potent inhibitor of polyamine biosynthesis that inhibits ornithine decarboxylase, adenosylmethionine decarboxylase and spermidine synthase. 386 Nov 82

Rats having a protein-free diet available ad libitum were fed a daily casein meal at the beginning of either the light- or the dark-phase of the day. A control group received a mixed-diet ad libitum. In all three groups, daily food ingestion was the same and casein corresponded to 12% of total intake. Liver activities of alanine, aspartate, ornithine and tyrosine aminotransferase, ornithine decarboxylase and serine dehydratase were assessed. In mixed-fed controls, all activities were low. Tyrosine aminotransferase and ornithine decarboxylase exhibited clear circadian rhythms of low amplitude. Feeding casein as a concentrated meal had no effect on aspartate aminotransferase. It depressed alanine aminotransferase and serine dehydratase activities. Tyrosine aminotransferase and ornithine decarboxylase exhibited rapid and strong stimulatory responses but, within 12 hours, returned to levels similar to those observed in mixed-fed controls. Ornithine aminotransferase was increased in the group receiving the casein meal during the light phase. It is concluded that the capacity for amino acid catabolism remains low in separately-fed animals, and that only tyrosine and especially ornithine, which may become limiting for urea synthesis, are actively metabolized. Thus, when high fluxes of amino acids reach the liver following the absorption of the casein meal, more amino acids are available for incorporation into newly synthesized proteins.
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PMID:Activity of several enzymes of amino acid catabolism in the liver of rats fed protein as a meal. 613 52

Our previous studies showed that polybrominated biphenyl (PBB) induced hepatic microsomal cytochrome P-450 in dairy cattle but did not elevate hepatic cytosolic ornithine decarboxylase or serum isocitrate dehydrogenase. These enzymes would be expected to increase during hepatotoxic injury and regeneration. Thus, PBB appeared to be a hepatotoxin in rats but not in cattle. In order to identify and confirm the response capability of bovine liver to hepatotoxins, we administered thioacetamide, a hepatotoxin known to induce hepatonecrosis, to a dairy calf. A progression of clinical signs of toxicosis was evident until the animal was moribund by 23 hr postdosing. Histolopathologic alterations in the liver included centrilobular necrosis with congestion and subcapsular microhemmorrhage. Marked changes in serum protein profiles were not noted. However, distinct increases in serum Fe and bilirubin occurred with progressing toxicosis, as did sharp declines in glucose and triglycerides. Serum lactic dehydrogenase, alkaline phosphatase, glutamic-oxaloacetic transaminase, isocitrate dehydrogenase and glutamic-pyruvate transaminase were elevated. Elevation of ornithine decarboxylase was dramatic when compared to the level in normal fetal bovine liver. From studies of its kinetic properties, bovine liver ornithine decarboxylase appears to have an apparent Km for ornithine decarboxylase of .45 mM. Liver homogenates from PBB-treated animals did not form inhibitors to ornithine decarboxylase. Compared with the thioacetamide-treated calf, the normal adult bovine, pregnant adult and 6-month fetus had relative activities of .2 .4 and 5.8%, respectively. These studies show that ornithine decarboxylase is low in liver of normal cattle, but is elevated markedly by agents that cause hepatonecrosis.
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PMID:Ornithine decarboxylase, serum isocitrate dehydrogenase and clinical chemistry changes during thioacetamide-induced hepatotoxicity in a calf. 734 23

We examined the polyamine metabolism in liver transplanted after cold ischemia and effects of putrescine administration on liver injury, liver regeneration, and survival rate after orthotopic liver transplantation in the rat. Male Wistar rats were used as donors and recipients. Grafts were stored in Euro-Collins solution for 6 h at 4 degrees C. Orthotopic liver transplantation was performed by the three cuff technique. The activities of aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase elevated and peaked 4 h after liver transplantation. Hepatic ornithine decarboxylase and spermidine/spermine N1-acetyltransferase activities were also elevated and peaked 8 h after the operation. In agreement with the increases in ornithine decarboxylase and spermidine/spermine N1-acetyltransferase activities, the putrescine content increased and spermidine content decreased in the transplanted liver. Putrescine administrated intraperitoneally improved the survival rate, decreased serum transaminase level and increased the [3H]thymidine incorporation into the liver DNA. These findings suggest that both biosynthetic and biodegradative pathways are stimulated in liver transplantation, resulting in the increase in the formation of putrescine from ornithine and from spermidine, and that putrescine administration improve the survival rate by protecting the damaged graft after cold ischemia and reperfusion and by stimulating liver regeneration.
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PMID:Polyamine metabolism in the rat liver after orthotopic liver transplantation. 749 79


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