Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The causes and clinical signs of hepatobiliary involvement in disease are many and varied and often are not referable directly to this organ system. Laboratory investigation frequently is necessary to rule hepatic disease in or out, to assess the functional impact on the liver, and to decide whether hepatic disease is the patient's primary problem or a complication of something else. The selection and interpretation of laboratory tests to resolve these problems is based on an understanding of relevant functional anatomy and pathophysiology. The mainstay of such assessment is hepatic enzymology, which can detect active disease in both hepatocytes and the biliary system. The hepatocellular pattern of disease is characterized by increases in leakage enzymes such as SDH, GLDH, and ALT and the cholestatic pattern by increases in induced enzymes (ALP and GGT). In general, enzymology does not allow the intensity or functional effect of hepatobiliary disease to be assessed, and quite severe hepatopathies may have only minimal enzyme abnormalities. For this reason, the primary biochemical data base for ruling hepatobiliary disease in or out always should involve some screening tests of hepatic function, such as albumin, protein, bilirubin, glucose, or urea determinations; as well as urinalysis to search for bilirubinuria and urobilinogenuria in hyperbilirubinemic patients and for ammonium biurate crystals when hyperammonemia or hepatic encephalopathy is suspected. Because the liver synthesizes most clotting factors, evaluation of blood coagulation is indicated when surgery is contemplated on patients with liver disease or when bleeding is present. Paired pre- and post-prandial determinations of serum bile acids are the preferred method for assessment of hepatobiliary function in dogs and cats. However, the BSP clearance test continues to be useful in the functional assessment of the liver as long as the dye remains available to veterinarians. Clearance of BSP is delayed in hepatocellular, cholestatic, and portosystemic disease as well as by severe extrahepatic circulatory disturbances, In general, this functional test is less sensitive than serum bile acids or the ammonia tolerance test in the recognition of hepatic encephalopathy caused by portosystemic anomalies. The objectives of biochemical screening of the liver are to establish the type (hepatocellular, biliary, or mixed), duration (acute, chronic), and stage (aggressive, convalescent) of hepatobiliary disease and to assess functional status.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Biochemical evaluation of the hepatobiliary system in dogs and cats. 267 13

Pathways of ammonia assimilation into glutamic acid and alanine in Bacillus polymyxa were investigated by 15N NMR spectroscopy in combination with measurements of the specific activities of glutamate dehydrogenase, glutamine synthetase, glutamate synthetase, alanine dehydrogenase, and glutamic-alanine transaminase. Ammonia was found to be assimilated into glutamic acid predominantly by NADPH-dependent glutamate dehydrogenase with a Km of 2.9 mM for NH4+ not only in ammonia-grown cells but also in nitrate-grown and nitrogen-fixing cells in which the intracellular NH4+ concentrations were 11.2, 1.04, and 1.5 mM, respectively. In ammonia-grown cells, the specific activity of alanine dehydrogenase was higher than that of glutamic-alanine transaminase, but the glutamate dehydrogenase/glutamic-alanine transaminase pathway was found to be the major pathway of 15NH4+ assimilation into [15N]alanine. The in vitro specific activities of glutamate dehydrogenase and glutamine synthetase, which represent the rates of synthesis of glutamic acid and glutamine, respectively, in the presence of enzyme-saturating concentrations of substrates and coenzymes are compared with the in vivo rates of biosynthesis of [15N]glutamic acid and [alpha,gamma-15N]glutamine observed by NMR, and implications of the results for factors limiting the rates of their biosynthesis in ammonia- and nitrate-grown cells are discussed.
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PMID:Ammonia assimilation in Bacillus polymyxa. 15N NMR and enzymatic studies. 288 2

The case records of 21 dogs with congenital portosystemic encephalopathy are reviewed. The disorder was most common in Australian cattledogs (blue heelers; 8 cases), Old English sheepdogs (3 cases) and Maltese terriers (3 cases). Extra-hepatic shunts occurred in small breeds, with the exception of 1 cattledog, while intra-hepatic shunts occurred in the medium to large breeds. The most common clinical pathology abnormalities were abnormal ammonia tolerance, mild to moderate increases in plasma alanine aminotransferase or alkaline phosphatase concentrations, decreased total serum protein concentrations, increased fasting ammonia concentrations and ammonium biurate crystalluria. Radiological examination revealed that all the dogs had a small liver. The kidneys were enlarged in 5 of 10 dogs in which kidney size could be estimated. Surgical ligation of an extra-hepatic shunt was successful in 2 of 4 dogs in which it was attempted. Medical management resulted in alleviation of clinical signs in 5 of 8 dogs. The period of successful treatment ranged from a few months to over a year.
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PMID:Canine congenital portosystemic encephalopathy. 319 May 91

1. A method is described for extracting separately mitochondrial and extramitochondrial enzymes from fat-cells prepared by collagenase digestion from rat epididymal fat-pads. The following distribution of enzymes has been observed (with the total activities of the enzymes as units/mg of fat-cell DNA at 25 degrees C given in parenthesis). Exclusively mitochondrial enzymes: glutamate dehydrogenase (1.8), NAD-isocitrate dehydrogenase (0.5), citrate synthase (5.2), pyruvate carboxylase (3.0); exclusively extramitochondrial enzymes: glucose 6-phosphate dehydrogenase (5.8), 6-phosphogluconate dehydrogenase (5.2), NADP-malate dehydrogenase (11.0), ATP-citrate lyase (5.1); enzymes present in both mitochondrial and extramitochondrial compartments: NADP-isocitrate dehydrogenase (3.7), NAD-malate dehydrogenase (330), aconitate hydratase (1.1), carnitine acetyltransferase (0.4), acetyl-CoA synthetase (1.0), aspartate aminotransferase (1.7), alanine aminotransferase (6.1). The mean DNA content of eight preparations of fat-cells was 109mug/g dry weight of cells. 2. Mitochondria showing respiratory control ratios of 3-6 with pyruvate, about 3 with succinate and P/O ratios of approaching 3 and 2 respectively have been isolated from fat-cells. From studies of rates of oxygen uptake and of swelling in iso-osmotic solutions of ammonium salts, it is concluded that fat-cell mitochondria are permeable to the monocarboxylic acids, pyruvate and acetate; that in the presence of phosphate they are permeable to malate and succinate and to a lesser extent oxaloacetate but not fumarate; and that in the presence of both malate and phosphate they are permeable to citrate, isocitrate and 2-oxoglutarate. In addition, isolated fat-cell mitochondria have been found to oxidize acetyl l-carnitine and, slowly, l-glycerol 3-phosphate. 3. It is concluded that the major means of transport of acetyl units into the cytoplasm for fatty acid synthesis is as citrate. Extensive transport as glutamate, 2-oxoglutarate and isocitrate, as acetate and as acetyl l-carnitine appears to be ruled out by the low activities of mitochondrial aconitate hydratase, mitochondrial acetyl-CoA hydrolyase and carnitine acetyltransferase respectively. Pathways whereby oxaloacetate generated in the cytoplasm during fatty acid synthesis by ATP-citrate lyase may be returned to mitochondria for further citrate synthesis are discussed. 4. It is also concluded that fat-cells contain pathways that will allow the excess of reducing power formed in the cytoplasm when adipose tissue is incubated in glucose and insulin to be transferred to mitochondria as l-glycerol 3-phosphate or malate. When adipose tissue is incubated in pyruvate alone, reducing power for fatty acid, l-glycerol 3-phosphate and lactate formation may be transferred to the cytoplasm as citrate and malate.
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PMID:The intracellular localization of enzymes in white-adipose-tissue fat-cells and permeability properties of fat-cell mitochondria. Transfer of acetyl units and reducing power between mitochondria and cytoplasm. 439 82

Crocodilians such as caimans and alligators are uricotelic and ammoniotelic animals. They are carnivorous but they excrete ammonium ions in an alkaline urine. The metabolic organization of the kidney of the Mississippi alligator was studied by measuring the renal metabolite profile, the activities of enzymes, and the behavior of kidney tubules in vitro. The liver and tail muscle were also studied. Both awake and anesthetized animals were in a state of low plasma bicarbonate and low blood pH with high plasma lactate concentration. This did not prevent the excretion of an alkaline urine (pH 7.76). alpha-Ketoglutarate was low in all three tissues and lactate was high. Glutamate concentration and glutamate dehydrogenase activity were highest in the kidney with a low equilibrium constant for alanine aminotransferase (KGPT). Glutaminase I was found only in the kidney. It could not be detected in liver or muscle. Glutamine synthetase was found only in the liver. Phosphoenolpyruvate carboxykinase (PEPCK) was present in both liver and kidney. Alanine aminotransferase and malic enzyme showed high activity in the kidney but were inconspicuous in liver and muscle. Malate dehydrogenase and lactate dehydrogenase were present in all three tissues. Renal tubules incubated with glutamine and alanine were ammoniagenic and gluconeogenic. Lactate was gluconeogenic. Enzyme activities were measured at both 30 and 37 degrees C. The studies on renal tubules were also performed at these two temperatures. Temperature had little effect on the data including acid-base values in the blood. Our findings demonstrate that the kidney of the alligator is perfectly equipped for various metabolic functions and especially for ammoniagenesis and gluconeogenesis.
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PMID:Metabolic machinery of the alligator kidney. 649 95

Glutamate dehydrogenase (GDH) and the transaminases namely aspartate aminotransferase (AAT) and alanine aminotransferase (AIAT) were estimated in the muscle, liver, kidney, and brain of control and ammonium acetate administered frogs. The results indicated tissue specific responses during induced ammonotoxemia. The inherent endogenous ammonia production decreased in all the tissues. 2-Keto glutarate production appears to be the other main adaptive feature as a result of slightly stepped up transdeamination patterns.
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PMID:Transamination and glutamate deamination in Rana hexadactyla during induced ammonia toxicity. 651 Oct 61

Effectiveness of surgically induced acute hepatic failure in pig and most suitable time to apply artificial support in hepatic coma are evaluated in this work. Five male pigs weighing about 30-35 kg are employed. Latero-lateral porto-caval shunt was performed; the vascular disconnection of liver was obtained by ligature of blood vessels. Ligature was also placed on main biliary way after cholecistectomy. Blood samples were obtained (at 0, 1, 2, 6, 12, 18, 24 hours) to essay serum bilirubin, alkaline phosphatase and GOT-GPT levels as index of cholestasis and necrosis. Porto-caval encephalopathy was evaluated by means of serum ammonium levels, aminoacid pattern and E.E.G. Serum aminoacid pattern was carefully determined; its changes were found similar in man during coma. All pigs died 24-36 hours after surgery with liver ischemic and necrosis. Clinical and laboratory data obtained in experimental conditions were found similar to picture of acute hepatic failure in man, confirming validity of our model.
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PMID:[Acute experimental hepatic insufficiency in pigs. Validity of a model with biohumoral and electroencephalographic monitoring]. 667 5

Renal adaptation to chronic metabolic acidosis was studies in Arbor Acre hens receiving ammonium chloride by stomach tube 0.75 g/kg/day during 6 days. During a 14-day study, it was shown that the animals could excrete as much as 60% of the acid load during ammonium chloride administration. At the same time urate excretion fell markedly but the renal contribution to urate excretion (14%) did not change. During acidosis, blood glutamine increased twofold and the tissue concentration of glutamine rose in both liver and kidney. Infusion of L-glutamine led to increased ammonia excretion and more so in acidotic animals. Glutaminase I, glutamate dehydrogenase, alanine aminotransferase (GPT), and malic enzyme activities increased in the kidney during acidosis but phosphoenolpyruvate carboxykinase (PEPCK) activity did not change. Glutaminase I was not found in the liver, but hepatic glutamine synthetase rose markedly during acidosis. Glutamine synthetase was not found in the kidney. Renal tubules incubated with glutamine and alanine were ammoniagenic and gluconeogenic to the same degree as rat tubules with the same increments in acidosis. Lactate was gluconeogenic without increment during acidosis. The present study indicates that the avian kidney adapts to chronic metabolic acidosis with similarities and differences when compared to dog and rat. Glutamine originating from the liver appears to be the major ammoniagenic substrate. Our data also support the hypothesis that hepatic urate synthesis is decreased during acidosis.
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PMID:The kidney of chicken adapts to chronic metabolic acidosis: in vivo and in vitro studies. 681 56

Mitochondrial and cytosolic alanine aminotransferases (EC 2.6.1.2) were partially purified (140- and 180-fold), respectively) from bovine brain cortex by means of (NH4)2SO4 precipitation, gel filtration on Sephadex G-150, and in-exchange chromatography on DEAE A-50 and characterized. The enzymes exhibited identical molecular weights (110,000 +/- 10,000) and pH optima (7.8), but were eluted from CM Sephadex C-50 at different ionic strengths. Isoelectric focusing of the enzymes indicated a pI value of 5.2 for the cytosolic enzyme and 7.2 for the mitochondrial enzyme. The Km values of the mitochondrial enzyme were 5.1 mM, 6.6 mM, 0.7 mM, and 0.4 mM and of the cytosolic isozyme were 30.3 mM, 4.3 mM, 0.7 mM, and 0.5 mM for alanine, glutamate, 2-oxoglutarate, and pyruvate, respectively. The results indicated that two forms of alanine aminotransferase exist in nerve tissue, which suggests that they may play different roles in the cellular metabolism of nerve tissue.
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PMID:Alanine aminotransferase in bovine brain: purification and properties. 708 11

Chronic acidosis evoked by a 7-day application of ammonium chloride in concentration of 2% increased the activity of glutamate decarboxylase (GAD) in renal homogenates of rats to approximately 160%. The enzyme activators, chlorides and adenosine triphosphate influenced in varying measures the GAD activity in renal homogenates of both controlled and acidotic animals. Whilst ATP was gradually loosing the activating effect, chlorides preserved it. The renal GAD is firmly bound on insoluble structures. The increase in GAD activity due to acidosis was accompanied by increasing permanence of this bind. After the substitution of ammonium chloride by drinking water, the return of the increased GAD activity to previous normal values lasted 7 days, whilst apparent normalization of the weight of experimental animals reoccurred on the first day. Subfractionation of the crude renal mitochondrial fraction by use of enzyme markers localized GAD in mitochondria. In renal homogenates the activities of GABA-transaminases were assessed. GABA-alpha-ketoglutarate transaminase was 5x more active than GABA-pyruvate transaminase. Acidosis resulted in augmentation of both transaminases--the first to 130%, the second to 160%. (Tab. 5, Fig. 3, Ref. 25.)
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PMID:[The effect of chronic acidosis on the activity of renal glutamate decarboxylase and GABA-transaminase]. 788 63


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