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)

Evidence is provided for the utilization of glutamine by calvaria and compact bone of rat. Glutamine was actively transported into calvaria, principally by sodium-dependent mechanisms; its uptake was significantly inhibited by neutral amino acids (alanine, proline, serine, asparagine) and glutamine analogs (L-glutamate-gamma-hydroxamate, albizziin). Glutamine was degraded to ammonia and glutamate by phosphate-dependent glutaminase, a mitochondrial enzyme present in both calvaria and compact bone. The enzyme exhibited an apparent Kmgln of 2.35 mM, a KactPO4 of 25 mM, and a broad pH optimum (7.5-9.5). It was inactivated by incubation of intact calvaria or bone homogenates with the glutamine analogs 6-diazo-5-oxo-L-norleucine (DON) and a 2-amino-4-oxo-5-chloropentanoic acid (chloroketone). Such treatment also severely inhibited (greater than 95%) both ammonia and 14CO2 formation from [U-14C]glutamine. Glutamate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase activities were measured in bone. Amino-oxyacetate, an aminotransferase inhibitor, inhibited 14CO2 formation from [U-14C]glutamine. The data indicate that glutamine can serve as a precursor of ammonia, glutamate, other amino acids (alanine, aspartate, ornithine, proline) and carbon dioxide in bone and that phosphate-dependent glutaminase, transaminases, and citric acid cycle activity contribute to the observed metabolism.
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PMID:Glutamine metabolism in bone. 613 80

384 hospitalized patients of both sexes were classified into drinkers and non-drinkers according to clinical criteria. On admission, we measured four blood parameters : glutamate dehydrogenase, gamma glutamyl transferase, aspartate aminotransferase and the mean corpuscular volume. the discriminating power of these laboratory parameters was evaluated by descriptive statistical tests and by the determination of their positive and negative predictive value. Glutamate dehydrogenase appears to present a sensitivity almost equivalent to that of gamma glutamyl transferase and a better specificity : this results in a more positive predictive value. The two other laboratory parameters are less discriminating.
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PMID:[Role of glutamate dehydrogenase in the biological detection of excessive drinkers]. 613 49

Glutamate dehydrogenase activity was determined in mitochondrial preparations from rat ventral prostate and rat kidney. Kinetic parameters of the ventral prostate enzyme were comparable to those for the kidney enzyme. Glutamate dehydrogenase activity in the direction of glutamate oxidative deamination was inhibited by alpha-ketoglutarate. However, the characteristics of alpha-ketoglutarate inhibition indicated that glutamate oxidation via glutamate dehydrogenase can occur at in vivo prostatic alpha-ketoglutarate levels. These results suggest that glutamate dehydrogenase activity in prostate may provide a continuous source of alpha-ketoglutarate for aspartate transamination to oxalacetate and ultimate citrate synthesis. In addition prostate mitochondria are able to couple the glutamic dehydrogenase reaction to aspartate aminotransferase. Under these conditions aspartate in the presence of glutamate and acetyl coenzyme A will result in a net synthesis of citrate. Consequently we propose an aspartate-glutamate pathway for citrate synthesis in prostate.
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PMID:Glutamate dehydrogenase and a proposed glutamate-aspartate pathway for citrate synthesis in rat ventral prostate. 615 Jan 22

Eleven soluble enzymes in the supernatant of bloodstream Trypanosoma brucei were compared for electrophoretic mobility and activity with those of T. brucei cultures grown in 3 different media. All bands of each enzyme found in the bloodstream form were also present in the cultured material, but extra bands of malate dehydrogenase (MDH) (EC 1.1.1.37), aspartate aminotransferase (ASAT) (EC 2.6.1.1), and in 2 to 6 cultures of isocitrate dehydrogenase (ICD) (EC 1.1.1.42) were present in culture forms but not in bloodstream forms. An interfering enzyme, peculiar to cultured T. brucei, which reacted with 2-oxoglutarate and possibly a trace amount of ammonium ions, ran with the fast-moving ASAT bands. Threonine dehydrogenase activity, high in cultured trypanosomes irrespective of the medium used but low in bloodstream trypanosomes, was markedly lower in Trypanosoma evansi and a much passaged T. brucei 8/18. Glucosephosphate isomerase activity on the other hand was high in bloodstream and low in cultured trypanosomes. Glutamate dehydrogenase activity was too low to record reliably in bloodstream trypanosomes, but could be clearly detected in cultured forms. As the differences point to some changes in gene expression between the two forms, culture material is likely to replace trypanosomes from living animals for electrophoretic characterization only when considerable comparative work has been done.
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PMID:The electrophoretic mobilities and activities of eleven enzymes of bloodstream and culture forms of Trypanosoma brucei compared. 645 Aug 96

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

Glutamate dehydrogenase activity in the liver of the rainbow trout increases when the animals are starved for four weeks. Glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in the kidney of rainbow trout kept in sea water (20% S) is significantly higher than in the kidney of rainbow trout kept in fresh water. Gill Na/K-ATPase activity in the rainbow trout is reduced significantly (44%) by starvation for four weeks. Most of the free amino acids investigated in the white muscle of the rainbow trout were present in significantly higher concentrations in animals fed in sea water than in animals fed in fresh water. The concentrations of these amino acids are even higher in the muscle of starved animals held in sea water than in fed animals held in sea water.
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PMID:Influence of nutrition on biochemical sea water adaptation of the rainbow trout (Salmo gairdneri richardson). 661 64

Glutamate-oxaloacetate transaminase (GOT; EC 2.6.1.1) occurs as two electrophoretically distinguishable isozymes in the copepod Tigriopus californicus. The slower-migrating form, referred to as GOT2 , is shown to be associated with the mitochondrial cell fraction. GOT2 phenotypes are inherited in typical Mendelian fashion, indicating that they are encoded by a nuclear gene. Allelic frequencies for electrophoretic variants of the two Got loci in 12 California populations of T. californicus show a sharp differentiation of local populations. Linkage studies demonstrated that Got-2 is linked to Got-1; a map of four loci in linkage group I is presented.
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PMID:Genetics of mitochondrial glutamate-oxaloacetate transaminase (GOT-2) in Tigriopus californicus. 673 50

Experiments performed in polyethylene glycol and with a divalent crosslinker indicate that both mitochondrial malate dehydrogenase and aspartate aminotransferase can form hetero enzyme--enzyme complexes with either glutamate dehydrogenase or citrate synthase. In general, these as previous results indicate that complexes with the aminotransferase are favored over those with malate dehydrogenase and complexes with glutamate dehydrogenase are favored over those with citrate synthase. When the levels of enzymes are low, the only detectable complex is between the aminotransferase and glutamate dehydrogenase. Under these conditions, palmitoyl-CoA is required for complexes between the other three enzyme pairs, however, palmitoyl-CoA also enhances interactions between glutamate dehydrogenase and the aminotransferase. DPNH disrupts complexes with malate dehydrogenase and has little effect on those with the aminotransferase, while oxalacetate disrupts complexes with citrate synthase but has little effect on those with glutamate dehydrogenase. The citrate synthase-aminotransferase complex was favored in the presence of DPNH plus malate, which disrupt the other three enzyme-enzyme complexes. Glutamate dehydrogenase has a higher affinity and capacity than citrate synthase for palmitoyl-CoA. Consequently, lower levels of palmitoyl-CoA are required to enhance interactions with glutamate dehydrogenase. Furthermore, glutamate dehydrogenase can compete with citrate synthase for palmitoyl-CoA and thus can prevent palmitoyl-CoA from enhancing interactions between citrate synthase and either malate dehydrogenase or the aminotransferase.
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PMID:Complexes between mitochondrial enzymes and either citrate synthase or glutamate dehydrogenase. 682 31

1. The two molecular forms of mitochondrial malate dehydrogenase are partly bound to the mitochondrial membranes. 2. The A form is located on the outer surface of the inner mitochondrial membrane and also in the intermembrane space. 3. The B form of the enzyme appears in the matrix and bound in part, probably, to the inner surface of the inner mitochondrial membrane. 4. Glutamate dehydrogenase, glutamate oxaloacetate transaminase, fumarase and lactate dehydrogenase are bound, to a greater or lesser extent, to the mitochondrial membranes, the fumarase having the highest degree of binding.
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PMID:Intramitochondrial location of the molecular forms of chicken liver mitochondrial malate dehydrogenase. 706

Holstein bull calves were used to determine the influence of degradable nitrogen and ration physical form on rumen epithelial transport and enzymic activity. Rations contained 30, 45 and 60% ruminal degradable nitrogen (RDN), each with three forms (ground hay, GR; chopped hay, CH; and all concentrate, CONC). Rumen tissue samples were obtained by biopsy (8 weeks) and at slaughter (20 weeks). Acetate transport across rumen epithelium increased between 8 and 20 weeks in calves fed GR and CH, but not in calves fed CONC. Propionate transport was highest in calves fed GR and lowest in calves fed CONC at both 8 and 20 weeks. Transport of acetate and propionate was incresed with increasing RDN at 20 weeks. There were no differences in ruminal tissue lactate production. Rumen papillae of calves fed CONC were abnormal in morphology and at 20 weeks dry mucosal weights (mg/cm2) were highest. Lactate dehydrogenase and NADP-malic dehydrogenase activities were not different. Propionyl CoA synthetase activity was higher in 20-week calves fed CONC, compared to GR to CH. Glutamate dehydrogenase and aspartate aminotransferase activities were highest in 20-week calves fed 60% RDN rations, regardless of physical form.
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PMID:Influence of ration physical form, ruminal degradable nitrogen and age on rumen epithelial propionate and acetate transport and some enzymatic activities. 744 67


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