Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study deals with the effect of atrazine on nitrogen metabolism in the liver and brain of fish. Significant changes were seen in the levels of proteins, free amino acids, ammonia, urea, glutamine and the activity levels of proteases, glucogenic aminotransferases, branched-chain aminotransferases, glutamate dehydrogenase, glutaminase, arginase, AMP deaminase and adenosine deaminase in both the tissues of fish exposed to sublethal concentration of atrazine. The study reflects a shift in nitrogen concentration of atrazine. The study reflects a shift in nitrogen metabolism in the tissues of fish for efficient mobilization of end products of protein catabolism as a consequence of atrazine.
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PMID:Modulations in nitrogen metabolism in the hepatic and neuronal tissues of fish, Tilapia mossambica exposed to atrazine. 185 31

At sublethal concentrations, cypermethrin caused a decrease in total proteins and an increase in free amino acids, protease, alanine aminotransferase and aspartate aminotransferase in liver, brain and gill tissues of Tilapia mossambica. Nitrogen metabolic profiles like ammonia, urea and glutamine were also elevated in all the tissues as a consequence of cypermethrin toxicity. Glutamate dehydrogenase, AMP deaminase and adenosine deaminase activity was also increased in the present study.
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PMID:Cypermethrin induced changes in nitrogen metabolism of fish, Tilapia mossambica. 187 79

In isolated hepatocytes from fasted rats, 0.5 mM adenosine inhibited gluconeogenesis from glutamine, lactate and pyruvate. This inhibition was due to adenosine conversion through adenosine kinase. An increase in ketone body release was only observed in the presence of lactate or pyruvate, and the two phenomena (i.e. inhibition of gluconeogenesis and increased ketone-body release) were linked. With alanine, dihydroxyacetone or serine as substrates, adenosine did not change gluconeogenesis; however, its conversion through adenosine kinase also inhibited gluconeogenesis. With asparagine as substrate, 0.5 mM adenosine increased gluconeogenesis; this increase was due to adenosine conversion through adenosine deaminase. However, adenosine conversion through adenosine kinase inhibited gluconeogenesis from asparagine. Thus, whatever the substrate used, adenosine conversion through adenosine kinase inhibited gluconeogenesis. The inhibitory effect of adenosine on gluconeogenesis cannot be related to the decrease in Pi concentration and to the increase in ATP pool. Beside its effect on gluconeogenesis, adenosine inhibited ketogenesis measured without added substrate; adenosine conversion through adenosine kinase was also involved in the inhibition of ketogenesis.
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PMID:Metabolism of adenosine through adenosine kinase inhibits gluconeogenesis in isolated rat hepatocytes. 215 47

Effects of repeated administration of benthiocarb on the nitrogen metabolism of hepatic and neuronal systems have been studied. Repeated benthiocarb treatment was associated with significant decrease in proteins with a concomitant increase in free amino acids (FAA) and specific activity levels of proteases suggesting impaired protein synthesis or elevated proteolysis. The glycogenic aminotransferases showed a significant elevation in both the tissues indicating high feeding of ketoacids into oxidative pathway for efficient operation of TCA cycle to combat energy crisis during induced benthiocarb stress. However, the activity levels of branched-chain aminotransferases decreased suggesting their reduced contribution of intermediates to TCA cycle. A comparative evaluation of the activity levels of ammonogenic enzymes, AMP deaminase, adenosine deaminase and glutamate dehydrogenase (GDH) indicated that ammonia was mostly contributed by nucleotide deamination rather than by oxidative deamination. GDH exhibited reduced activity due to low availability of glutamate. In accordance with increased levels of urea, the activity levels of arginase, a terminal enzyme of urea cycle was increased suggesting increased urea cycle operation in order to combat the increased ammonia content. As the presence of urea cycle in the brain is rather doubtful, the conversion of ammonia to glutamine for the synthesis of GABA is envisaged in brain whereas in liver, excess ammonia was converted to urea through ornithine-arginine reacting system. The increased glutaminase activity observed during benthiocarb intoxication is accounted for counteracting acidosis or maintenance of metabolic homeostasis. Arginase, a terminal enzyme of ornithine cycle showed increased activity denoting the efficient potentiality of tissues to avert ammonia toxicity. The changes observed in tissues of rat administered with benthiocarb reflects a shift in nitrogen metabolism for efficient mobilization of end products of protein catabolism.
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PMID:Perturbations in nitrogen metabolism of brain and liver of rat following repeated benthiocarb administration. 266 46

We have determined the mutation in a child with partial adenosine deaminase (ADA) deficiency who is phenotypically homozygous for a mutant ADA gene encoding a heat-labile enzyme (Am. J. Hum. Genet. 38: 13-25). Sequencing of cDNA demonstrated a C to A transversion that results in the replacement of a proline by a glutamine residue at codon 297. As this mutation generated a new recognition site in exon 10 of genomic DNA for the enzyme Alu I, Southern blot analysis was used to establish that this child was indeed homozygous for the mutation. The abnormal restriction fragment generated by this mutation was also found in a second partially ADA-deficient patient who phenotypically is a genetic compound and also expresses a heat-labile ADA (in addition to a more acidic than normal ADA) (Am. J. Hum. Genet. 38: 13-25). Sequencing of cDNA clones from the second patient established the identical codon 297 mutation. Transfection of the mutant cDNA into heterologous cells resulted in expression of a heat-labile ADA of normal electrophoretic mobility and isoelectric point, properties exhibited by the ADA in the patients' cells.
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PMID:Identification of a point mutation resulting in a heat-labile adenosine deaminase (ADA) in two unrelated children with partial ADA deficiency. 278 88

Deficiency of adenosine deaminase (ADA) is the cause of an autosomal recessive form of immunodeficiency. We sought to define, at a molecular level, the mutations responsible for ADA deficiency in the cell line GM-1715, derived from an immunodeficient patient. Full-length complementary DNA (cDNA) for ADA was synthesized and cloned from the cell line. Sequence analysis of the clones revealed a point mutation in codon 101 (CGG to CAG) that predicts an amino acid change from arginine to glutamine. Southern blot analysis, based on silent polymorphisms in the cDNA sequence, indicated that only one of the defective alleles of the GM-1715 line had been sequenced. The mutation that was identified appears to be responsible for the loss of function in this allele, since the predicted primary structure of the enzyme is otherwise entirely normal.
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PMID:Identification of a point mutation in the adenosine deaminase gene responsible for immunodeficiency. 383 2

1. Tubule fragments were isolated from renal cortex of fed rats. 2. Gluconeogenesis from lactate was significantly increased by low concentrations of exogenous ATP, ADP, AMP adenylyl (beta, gamma-methylene)diphosphonate and, to a lesser extent, by ITP and inosine. GTP was slightly inhibitory. Hypoxanthine was ineffective. Exogenous adenosine deaminase slightly decreased gluconeogenesis and was additive in effect to GTP. Adenosine deaminase did not abolish the stimulatory effects of ATP or cyclic AMP. 3. 40 microM ATP also stimulated gluconeogenesis from pyruvate, malate, succinate, 2-oxoglutarate and glutamine, but had no effect when glycerol or fructose were used as substrates. 4. With lactate as substrate the effect of 40 microM ATP was additive to the maximal stimulations of gluconeogenesis seen with 1 microM noradrenalin or 0.1 microM angiotensin II, but was not additive to the stimulatory effect of 0.1 mM cyclic AMP. 5.40 microM ATP had no effect upon either the tubule content of cyclic AMP or upon 45Ca efflux from prelabelled tubules. 6. Addition of ouabain or removal of extracellular K+ diminished the stimulatory effects of ATP and cyclic AMP. 7. Extracellular ATP was rapidly metabolized by tubule fragments, with resulting accumulation of adenosine. Further metabolism resulting in formation of inosine, hypoxanthine, xanthine and uric acid was also observed. Cyclic AMP was metabolized less rapidly, with no accumulation of adenosine. 8. The effects of purinergic agents on gluconeogenesis are discussed.
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PMID:Stimulation of renal gluconeogenesis by exogenous adenine nucleotides. 629 8

Changes in oxidative metabolism were studied in hepatopancreas, muscle, and hemolymph of the edible crab Scylla serrata, exposed to a sublethal concentration (2.5 ppm) of cadmium chloride. A significant decrease in glycogen, total carbohydrates, and pyruvate and an increase in lactate levels in hepatopancreas and muscle were observed. Hemolymph sugar levels were increased in experimental crabs. An increase in phosphorylase suggested increased glycogenolysis during cadmium toxicity. The decrease in lactate dehydrogenase activity and the increase in lactate content indicated reduced mobilization of pyruvate into the citric acid cycle. Krebs cycle enzymes such as succinate dehydrogenase and malate dehydrogenase were found to be decreased, suggesting impairment of mitochondrial oxidative metabolism as a consequence of cadmium toxicity. Glucose-6-phosphate dehydrogenase activity was increased, suggesting enhanced oxidation of glucose by the HMP pathway. Cytochrome-c oxidase and Mg2+ ATPase activity levels decreased, indicating impaired energy synthesis during cadmium stress. Acid and alkaline phosphatase activities increased, suggesting enhanced breakdown of phosphates to release energy in view of impaired ATPase system during cadmium exposure. A significant decrease in protein and free amino acid and an increase in ammonia, urea, and glutamine levels were observed in the tissues during exposure. An increase in protease, alanine aminotransaminase, and aspartate aminotransaminase suggested increased proteolysis and transamination of amino acids. The increase in glutamate dehydrogenase, AMP deaminase, and adenosine deaminase indicated increased ammonia production. The increased arginase and glutamine synthetase suggested the detoxification or mobilization of ammonia toward the production of urea and glutamine. These results suggest that cadmium affects oxidative metabolism and induces hyperammonemia, and crabs switch over their metabolic profiles toward compensatory mechanisms for the survivability in cadmium-polluted habitats.
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PMID:Changes in oxidative metabolism in selected tissues of the crab (Scylla serrata) in response to cadmium toxicity. 753 86

Blood transfusions have been repeatedly shown to be immunosuppressive in nature. The intracellular mechanisms of this immunosuppression have not been extensively investigated. We investigated the effect of blood transfusions on lymphocyte intracellular metabolism of glucose and amino acids, as well as levels of adenosine deaminase activity and nucleotide triphosphate concentrations. Blood transfusions were found to increase the rate of glucose and glutamine metabolism, to increase nucleotide triphosphate concentrations, and to increase the level of adenosine deaminase activity. This increased level of lymphocyte metabolism in the face of immunosuppression would appear to indicate that the transfusion-induced immunosuppression is an active dynamic process.
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PMID:Effect of blood transfusion on immune function. IX. Effect on lymphocyte metabolism. 841 9

We report three novel adenosine deaminase (ADA) mutations with interesting implications. A Somali child with severe combined immunodeficiency disease (SCID) had reduced ADA mRNA in T cells and was homozygous for the nonsense mutation Q3X. Unexpectedly, her healthy father was a compound ADA heterozygote whose second allele carried a 'partial' mutation, R142Q, due to a G-->A transition of a CpG dinucleotide. A C-->T transition of the same CpG produced a nonsense mutation, R142X, in two homozygous Canadian Mennonite infants with SCID. The severe and healthy phenotypes associated with R142X and R142Q, the high frequency of 'partial' ADA mutations arising from CpGs in healthy individuals of African descent and the presence of CAA (glutamine) at codon 142 in murine ADA, suggest selection for replacement of this CpG hotspot by CpA during ADA evolution. R142X, located within a purine-rich segment at nt 62/116 of exon 5, caused skipping of the exon, possibly by disrupting a splicing enhancer. Absence of exon 5 in T cell ADA mRNA and low ADA activity in T cells and erythrocytes obtained at age 18-22 months from one of the Mennonite children, indicate limited expression of a normal ADA cDNA from retrovirally transduced CD34+ umbilical cord leukocytes infused shortly after birth in an attempt at stem cell gene therapy.
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PMID:Three new adenosine deaminase mutations that define a splicing enhancer and cause severe and partial phenotypes: implications for evolution of a CpG hotspot and expression of a transduced ADA cDNA. 858 84


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