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)

Because of the difficulties in drawing blood for clinical chemistry in small laboratory animals there exist many methods for sampling blood and the preparation of serum, none of which is generally accepted or well standardised. It was the aim of this study to investigate the effects of sampling techniques on normal values of enzyme activities in the serum of rat and mouse. The activities of the following enzymes were determined: sorbitol dehydrogenase, lactate dehydrogenase, malate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, pyruvate kinase, creatine kinase, myokinase, alkaline phosphatase and leucine aminopeptidase. In addition plasmaproteins, urea and inorganic phosphorus were measured. In rats blood was obtained from the following sites: retroorbital venous plexus, jugular vein, heart and ventral aorta. In mice blood was sampled from the jugular vein and the ventral aorta. Shifts of water from the interstitial to the intravascular space due to hypovolemia occurring during the experimental procedure were followed up by measuring the hematocrit and the distribution of radioiodide labelled albumin. In rats the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase, pyruvate kinase, creatine kinase and myokinase found in blood serum obtained from the retroorbital venous plexus and the ventral aorta were too high compared to the other sampling sites. Activities of alkaline phosphatase and alanine aminotransferase were slightly elevated when blood was sampled from the punctured retroorbital venous plexus. Small differences in plasmaproteins and hematocrit values were found to be due to acute shifts of water within the extracellular space. In mice the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase and myokinase were found to be too high in blood serum obtained from the ventral aorta. Efflux of enzymes from damaged cells and the interstitial space ive caused erroneous results too, but only to a minor extent. The most reliable method for blood sampling in rat and mouse is the cannulation of the jugular vein. The heart puncture can be recommended too. Attention should be paid, however, to the possibility of aspirating disrupted muscle cells through the inserted needle.
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PMID:[Effects of blood sampling on enzyme activities in the serum of small laboratory animals (author's transl)]. 108 84

An assessment of the Gilford Automatic Enzyme Analyser was conducted over a period of one year. The optics of the instrument were satisfactory with regard to accuracy of wavelength selection and linearity of absorbance response. Excellent precision was obtained for both absorbance readings and operation of the dispenser pump. Carry-over within the microflow-cell was low. The method of operation recommended by the manufacturers for enzyme determinations failed to take account of endogenous blank reactions which could lead to significant error. When revised methods utilising a pre-incubation stage and initiation with a single substrate were employed, the results correlated well with those obtained with standard automatic (LKB 8600) and manual (Pye Unicam SP 800) kinetic systems for aspartate and alanine aminotransferase, creatine phosphokinase and alpha-hydroxybutyrate dehydrogenase, and the precision at all activity levels was satisfactory. Acceptable precision could not be obtained over the clinical range for enzyme assays requiring a blank determination on each sample (5'-nucleotidase and adenosine deaminase) and those with very low normal serum activities (isocitrate dehydrogenase and glutamate dehydrogenase). These limitations appeared to be due to relative insensitivity of the transducer response and liability to optical disturbance. This apart, the instrument has many advantages over alternative equipment.
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PMID:An evaluation of the Gilford 3400 automatic enzyme analyser. 114 90

The only exogenous substrates oxidized by mitochondria isolated from the flight muscle of the Japanese beetle (Popillia japonica) are proline, pyruvate and glycerol 3-phosphate. The highest rate of oxygen consumption is obtained with proline. The oxidation of proline leads to the production of more NH3 than alanine, indicating a functioning glutamate dehydrogenase (EC 1.4.1.2). Studies of mitochondrial extracts confirm the presence of a very active glutamate dehydrogenase, and this enzyme is found to be activated by ADP and inhibited by ATP. These extracts also show high alanine aminotransferase activity (EC 2.6.1.2) and a uniquely active "malic' enzyme (EC 1.1.1.39). The "malic' enzyme is activated by succinate and inhibited by ATP and by pyruvate. It is suggested that the input of tricarboxylate-cycle intermediate from proline oxidation is balanced by the formation of pyruvate from malate, and the complete oxidation of the majority of the pyruvate. Studies of the steady-state concentrations of mitochondrial CoASH and CoA thioesters during proline oxidation show a high succinyl (3-carboxypropionyl)-CoA content which falls on activating respiration with ADP. There is a concomitant rise in CoASH. However, the reverse transition, from state-3 to state-4 respiration, causes only very slight changes in acylation. The reasons for this are discussed. Studies of the mitochondrial content of glutamate, 2-oxoglutarate, malate, pyruvate, citrate and isocitrate during the same phases of proline oxidation give results consistent with control at the level of glutamate dehydrogenase and isocitrate dehydrogenase during proline oxidation, with the possibility of further control at "malic' enzyme. During the oxidation of pyruvate all of the tricarboxylate-cycle intermediates and NAD(P)H follow the pattern of changes described in the blowfly (Johnson & Hansford, 1975; Hansford, 1974) and isocitrate dehydrogenase is identified as the primary site of control.?2OAuthor
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PMID:The nature and control of the tricarboxylate cycle in beetle flight muscle. 120 Sep 85

Response characteristics are presented for a dual-enzyme fiber-optic biosensor for glutamate. An enzyme layer composed of glutamate dehydrogenase (GDH) and glutamate-pyruvate transaminase (GPT) is used to produce reduced nicotinamide adenine dinucleotide (NADH) at the tip of a fiber-optic probe. NADH luminescence is monitored through this probe and the measured fluorescence intensity is related to the concentration of glutamate. GDH catalyzes the formation of NADH, and GPT drives the GDH reaction by removing a reaction product and regenerating glutamate. Optimal response is obtained in a pH 7.4 Tris-HCl buffer maintained at 25 degrees C in the presence of 4 mM NAD+ and 10 mM L-alanine. The temperature profile reveals a strong negative temperature effect which is attributed to the temperature dependency of NADH luminescence. Under optimal conditions, the sensor sensitivity is 0.127 nA/microM over the 1-10 microM concentration range, the detection limit is 0.13 microM, and response times range from 4 to 8 min. The sensor response is stable for 12 days when stored at 4 degrees C. Selectivity for glutamate is excellent over most of the common amino acids as well as ascorbic acid, uric acid, taurine, and GABA. Only slight responses were observed for glutamine and lysine. The effect of ammonia on the glutamate response was found to be minimal at total ammonia nitrogen concentrations as high as 200 microM.
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PMID:Dual-enzyme fiber-optic biosensor for glutamate based on reduced nicotinamide adenine dinucleotide luminescence. 135 Apr 33

The effect of subacute and acute doses of ammonium acetate was studied on the production of 14CO2 from 14C-labeled glutamate and aspartate by neuronal perikarya and synaptosomes isolated from rat cerebellum. Studies with inhibitors for aminotransferases (aminooxy acetic acid) and glutamate dehydrogenase (glutamic acid diethyl ester) indicated that transamination reactions play a major role in this process. There was a suppression in this process in hyperammonemic states. Activities of the enzymes, aspartate aminotransferase, alanine aminotransferase, glutamate dehydrogenase and glutaminase were decreased in both preparations in hyperammonemic states. Activity of glutamine synthetase was unaltered.
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PMID:Ammonia-induced alterations in the metabolism of glutamate and aspartate in neuronal perikarya and synaptosomes of rat cerebellum. 135 57

Pathophysiological concentrations of ammonia, both in vivo and in vitro, suppressed the production of 14CO2 from 14C-labelled glutamate and aspartate in astrocytes isolated from the rat cerebellum. Suppression of 14CO2 production with (aminooxy)acetic acid but not with glutamic acid diethyl ester indicated that transamination plays a major role in the oxidation of glutamate carbons. Activities of the enzymes, aspartate amino-transferase, alanine aminotransferase and glutaminase were decreased while those of glutamate dehydrogenase and glutamine synthetase were enhanced in the cerebellar astrocytes during hyperammonemic states. These results suggest an impairment of astrocytic glutamate metabolism during hyperammonemia.
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PMID:Hyperammonemic alterations in the metabolism of glutamate and aspartate in rat cerebellar astrocytes. 135 96

Isozyme analysis of L-alanine:2-oxoglutarate aminotransferase (ALT) in maize indicates that there are three genes encoding this enzyme activity. Two of the gene products interact with each other to form heterodimers, while the third gene product does not interact with the other two. Another isozyme that appears after gel electrophoresis and ALT staining is shown to be glutamate dehydrogenase-1. Anaerobic treatment does not result in increased ALT levels, indicating that the previously reported increase in alanine levels caused by this treatment may be due to increases in the level of pyruvate, a substrate of ALT.
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PMID:Analysis of L-alanine:2-oxoglutarate aminotransferase isozymes in maize. 144 81

The determination of ammonia in plasma, using glutamate dehydrogenase, is complicated by non-specific oxidation of the coenzyme, promoted by components of the sample matrix. Measurements performed with appropriate plasma blanks show that 2'-phosphorylated coenzymes (NADPH, deamino-NADPH) are much less oxidized than NADH. By adding lactate dehydrogenase, NADH oxidation by endogenous pyruvate can be completed within a short time. Considerable consumption of coenzyme occurs, however, and endogenous L-alanine aminotransferase also represents a possible source of interference. The results of ammonia determinations using deamino-NADPH (y) or NADPH (x) were identical (a = 0.0 mumol/l, b = 1.00; r = 0.996, n = 62). With NADH as the coenzyme, the method displays adequate specificity only at high sample dilution, e.g. in the measurement of urea after conversion to ammonia.
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PMID:Which is the appropriate coenzyme for the measurement of ammonia with glutamate dehydrogenase? 145 16

Giardia lamblia is believed to be the earliest branching derivative from the eucaryotic lineage. Genomic and cDNA clones encoding the giardia NADP-dependent glutamate dehydrogenase have been isolated and characterized. Southern hydridization using genomic DNA indicates that the gene encoding this activity is unique and single copy. Primer extension, S1 nuclease protection, and genomic and cDNA sequence analysis demonstrate that gene transcripts are initiated within a conserved AT-rich sequence element immediately preceding the ATG translation initiation codon and the short 5' untranslated region is not extended by transsplicing. The open reading frame is 1350 nucleotides in length and encodes a protein of 449 amino acids. The reading frame is not interrupted by introns and the primary transcript is probably not subjected to RNA editing. In the strictly anaerobic metabolism of giardia, NADP-dependent glutamate dehydrogenase activity participates along with alanine aminotransferase, in the cyclic dissipation of reducing equivalents (NADPH) through the conversion of pyruvate to alanine. The deduced amino acid sequence of the giardia protein exhibits substantial homology to numerous fungal and eubacterial NADP-dependent glutamate dehydrogenases. Comparisons of alignment gap positions and amino acid identities indicate that the giardia sequence is at least as similar or more similar to the eubacterial sequence than it is to the fungal sequence. This supports the hypothesis that giardia diverged very early from the eucaryotic lineage.
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PMID:Isolation and characterization of a NADP-dependent glutamate dehydrogenase gene from the primitive eucaryote Giardia lamblia. 155 91

Periportal (pp) or perivenous (pv) liver parenchymal cells from female adult Uje: WIST rats were isolated after retro- or antegrade digitonin infusion followed by collagenase perfusion in the opposite direction. The morphological results revealed a distinct acinar-related destruction of the pv- or pp-zone by digitonin. The remaining cells of the respective other zone showed a good structural maintenance. After subsequent conventional collagenase perfusion the yield, viability and structural integrity of the isolated hepatocytes were high. The zonal cell separation was indicated by significant differences in the pp marker glucose-6-phosphatase and the pv marker glutamine synthetase found in the isolated pp or pv cell populations. Under our experimental conditions including the use of female rats, the alanine aminotransferase and glutamate dehydrogenase as well as ethylmorphine N-demethylase and ethoxycoumarin O-deethylase activities were evenly distributed in both preparations. Under stimulating conditions the capacity for urea synthesis was similar in both pv and pp cells.
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PMID:Biochemical and morphological studies on perivenous and periportal liver parenchymal cells from female rats isolated by digitonin-collagenase method. 168 Jul 46


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