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:3.5.4.4 (adenosine deaminase)
5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During the relatively recent period in which normal genes for most red cell enzymes have been isolated, the techniques of molecular biology have been applied to the studies of erythroenzymopathy. Single nucleotide substitutions have been identified in aldolase, triosephosphate isomerase, glucose 6-phosphate dehydrogenase, and adenylate kinase variants by the cloning and nucleotide sequence of the patients' genes. Up to now, all of the enzyme-deficient variants which have been investigated have been caused by point mutations. An exception is a hemolytic anemia secondary to increased adenosine deaminase (ADA) activity. Red cell ADA activity increases on the order of a hundred-fold in affected individuals. The basic abnormality appears to result from overproduction of structurally normal enzyme due to abnormal transcriptional or translational efficiency.
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PMID:Recent progress in the molecular genetic analysis of erythroenzymopathy. 216 22

A kindred with an autosomal dominant form of chronic hemolytic anemia has been found to have a 40- to 70-fold elevation in erythrocyte adenosine deaminase (ADA) activity in association with depletion of red blood cell (RBC) ATP pools. ADA activities in B lymphoblasts, skin fibroblasts, and granulocytes were normal. There were no alterations in the kinetic properties of partially purified proband ADA. We have shown by Western blot analysis that the elevation in ADA activity is accompanied by a corresponding increase in the amount of immunoreactive ADA protein. Southern blot analysis of proband DNA ruled out gene amplification and revealed no gross insertions, deletions, or rearrangements in the ADA gene. Northern blot analysis demonstrated a marked increase in the amount of ADA mRNA in proband and sibling reticulocytes compared to high reticulocyte controls. ADA mRNA levels in B lymphoblasts from the proband, sibling, and GM558 cell line were normal. Cloning and sequencing of proband reticulocyte cDNA revealed normal ADA mRNA sequence. No polymorphisms were detected among the seven clones studied. RNase mapping of the 5'- and 3'-non-coding sequences confirmed the quantitative increase in reticulocyte ADA mRNA and verified that these regions were normal in length and sequence. Southern blot analysis of DNA from four affected and three unaffected family members revealed two restriction fragment length polymorphisms (RFLPs) which segregate with the ADA allele from the unaffected grandfather. Both RFLPs are present in the unaffected grandchild and absent in the affected grandchild. These findings are consistent with a cis- mutation within the ADA gene, but they do not rule out a trans- mutation affecting some non-ADA regulatory factor. We conclude that erythrocyte-specific ADA overproduction is associated with increased amounts of structurally normal ADA mRNA. This increase may result from either increased transcription of the ADA gene or altered post-transcriptional processing resulting in increased stability of the RNA transcript. Further elucidation of the defect should provide valuable insights into the normal tissue-specific regulation of the ADA gene and the mechanisms by which erythroid cells regulate gene expression during differentiation.
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PMID:Erythrocyte-specific overproduction of adenosine deaminase: molecular genetic studies. 262 27

Since the discovery of glucose-6-phosphate dehydrogenase (G6PD) deficiency and pyruvate kinase deficiency, erythroenzymopathies associated with hereditary hemolytic anemia have been extensively investigated. Kinetic and electrophoretic studies have shown that most erythroenzymopathies are caused by the production of a mutant enzyme. Single amino acid substitutions have been determined in G6PD and phosphoglycerate kinase variants by studies of the enzyme. Except for these two enzymes, it has been difficult to purify and to characterize the patient's enzyme because of the low protein contents in red blood cells. Recent advance in recombinant DNA technology has made possible the isolation of normal genomic DNA or cDNA for several enzymes. These results permit us to study the molecular basis of erythroenzymopathies at the nucleotide level. Single base substitutions have been identified in aldolase, triosephosphate isomerase, G6PD and adenylate kinase variants by the cloning and nucleotide sequence of the patients' genes. To date, all of the enzyme-deficient variants which have been investigated are caused by point mutations. An exception is a hemolytic anemia secondary to increased adenosine deaminase (ADA) activity. Red cell ADA activity increases on the order of a hundred-fold in affected individuals. The basic abnormality appears to result from overproduction of structurally normal enzyme due to abnormal translational efficiency.
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PMID:[Pathophysiology and laboratory tests of hemolytic anemia: with special reference to erythroenzymopathies]. 269 73

A marked tissue-specific increase in erythrocyte adenosine deaminase (ADA) activity is associated with an autosomal dominantly inherited hemolytic anemia. We investigated the molecular basis of ADA overproduction by studying reticulocyte ADA mRNA from affected individuals. Analysis of proband reticulocyte ADA cDNA clones revealed normal sequence. RNase mapping demonstrated that the amount of ADA mRNA in affected reticulocytes was greater than the amount in normal B lymphoblasts, whereas ADA mRNA was undetectable in normal reticulocytes. The 5'- and 3'-untranslated regions of reticulocyte and B-lymphoblast ADA mRNAs from affected individuals were structurally indistinguishable from those of normal B lymphoblasts. Northern blot analysis performed under stringent hybridization and washing conditions confirmed a markedly increased amount of reticulocyte ADA mRNA in affected individuals as compared with controls. We conclude that the RBC-specific overexpression of ADA in this disorder occurs at the mRNA level.
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PMID:Erythrocyte adenosine deaminase overproduction in hereditary hemolytic anemia. 275 23

The human erythrocyte generates high-energy adenosine triphosphate by anaerobic glycolysis and cycles oxidized and reduced nicotinamide adenine dinucleotide phosphate by the aerobic pentose phosphate shunt pathway. Certain enzymopathies of the pentose phosphate shunt are associated with hemolysis resulting from oxidative denaturation of hemoglobin. Glucose-6-phosphate dehydrogenase deficiency, an X-chromosome-linked disorder, is the prototype of these diseases and is genetically and clinically polymorphic. Six enzymopathies of anaerobic glycolysis cause hemolytic anemia; lactate dehydrogenase deficiency does not. In 2,3-diphosphoglycerate mutase deficiency, 2,3-diphosphoglycerate is greatly reduced and asymptomatic polycythemia is noted. Pyrimidine-5'-nucleotidase deficiency, an enzymopathy of nucleotide metabolism, is characterized by intracellular accumulations of pyrimidine-containing nucleotides, marked basophilic stippling on the stained blood film, splenomegaly, and hemolysis. Lead inhibits the nucleotidase and an identical syndrome occurs during severe lead poisoning. Hemolysis also accompanies an unusual enzymopathy characterized by a 40- to 70-fold increase (not decrease) in adenosine deaminase activity.
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PMID:Hemolytic anemias and erythrocyte enzymopathies. 299 Feb 76

A 4-fold increase of red blood cell adenosine deaminase (ADA) activity was found in a patient without haemolytic anaemia, but with mild anisopoikilocytosis. High-performance liquid chromatography showed a 40% reduction of adenosine-5'-triphosphate (ATP) while all the other nucleotides were in normal ranges. The patient's parents (first cousins) and a brother displayed the same enzyme activities as the controls. This observation suggests that mild increases of ADA activity is neither a marker for congenital hypoplastic anaemia as previously reported nor associated with haemolytic anaemia.
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PMID:Increased erythrocyte adenosine deaminase activity without haemolytic anaemia. 394 58

By light and electron microscopy, we observed foamy cells in the spleens from a patient with hemolytic anemia due to red cell adenosine deaminase (ADA) overproduction, a patient with rheumatoid arthritis (RA) treated with gold, and patients with idiopathic thrombocytopenic purpura (ITP). The foamy cells associated with red cell ADA overproduction were essentially similar to Gaucher-like cells described in patients with thalassemia, and it was suggested that the accelerated destruction of red cells was one of the factors responsible for the development of foamy cells. Foamy cells in ITP and RA were closely associated with an increased destruction of platelets in the spleen. Morphologic transitions between phagocytosed platelets and myelin-like materials were traced in these disorders. In RA, however, foamy cells were heterogeneous from an ultrastructural standpoint, with different cytoplasmic inclusions. In addition to myelin-like materials, dense bodies, vacuoles with flocculent materials, and gold were noted in most of foamy cells. As gold compounds are known to inhibit lysosomal enzymes, we surmise that an acquired disturbance in lysosomal digestion is partially responsible for the accumulation of intermediate metabolites. In the pathogenesis of foamy cells associated with blood cell dyscrasia, the accelerated destruction of blood cells and/or acquired disorders in catabolic pathways within the macrophages are suggested to be the underlying mechanism of an intralysosomal accumulation of incompletely degraded cellular debris.
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PMID:Three kinds of foamy cells in the spleen: comparative histochemical and ultrastructural studies. 404 43

The anucleate mature erythrocyte also lacks ribosomes and mitochondria and thus cannot synthesize enzymes or derive energy from the Krebs citric acid cycle. Nevertheless, the red blood cell is metabolically active and contains numerous residual enzymes and their products which are essential for its survival and normal functioning. Enzyme deficiencies in the Embden-Myerhoff glycolytic pathway can result in nonspherocytic hemolytic anemia (NSHA), and some are also associated with neuromuscular or neurologic disorders. Glucose-6-phosphate dehydrogenase deficiency in the hexose monophosphate shunt also results in hemolytic anemia, especially following exposure to various drugs. Defects in glutathione synthesis and pyrimidine 5'-nucleotidase deficiency also cause NSHA, as does increased adenosine deaminase activity. Gluthathione synthetase deficiency which is not limited to the red cell also presents as oxoprolinuria with neurologic signs. All red cell enzyme defects appear as single gene errors, in most cases recessive in inheritance, either autosomal of X-linked.
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PMID:Clinical consequences of enzyme deficiencies in the erythrocyte. 625 20

The maturing reticulocyte degrades ribosomal RNA to constituent ribonucleoside phosphates. Guanosine ribonucleotides are retained only in small amounts and pyrimidine ribonucleotides only in trace quantities. In the mature erythrocyte more than 97% of total nucleotides are the interconvertible adenosine mono-, di-, and triphosphates. High energy ATP fuels most of the reactions required to sustain viability. Unable to synthesize adenosine phosphates from small precursor molecules, the red cell relies on certain salvage pathways to replenish its losses from the adenosine phosphate pool. The most important of these involve adenosine. Adenylate kinase deficiency, when severe, is associated with nonspherocytic hemolytic anemia. A genetically-determined deficiency of pyrimidine 5'-nucleotidase prevents the normal dephosphorylation of pyrimidine ribonucleotides, and hence is characterized by the unique accumulation of pyrimidine phosphates intracellularly. Other features are chronic hemolytic anemia, splenomegaly, and a profound increase in basophilic stippling on the stained blood film. The syndrome is transmitted as an autosomal recessive disorder. A similar syndrome is found in severe lead poisoning as a consequence of nucleotidase inhibition by lead. An inherited, dominantly transmitted hemolytic anemia associated with low red cell ATP and a 45-70 fold increase in the enzymatic activity of adenosine deaminase has also been documented. The undefined molecular lesion appears to involve overproduction of an entirely normal enzyme protein. Severe deficiency of either of two sequential enzymes of purine metabolism, adenosine deaminase anemia, but by excessive accumulations of deoxyribonucleotides within red cells and lymphocytes. The clinical counterpart of each is a severe immunodeficiency state secondary to lymphopenia and lymphocyte dysfunction. Certain other rare clinical syndromes involving disturbed nucleotide metabolism also are detectable by red cell assay procedures.
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PMID:Erythrocyte disorders of purine and pyrimidine metabolism. 625 19

Using recently established ICSH recommended methods, red cell pyruvate kinases (PK) of 20 patients with PK deficiency were characterized and 7 new PK variants were found. Analysis of partially purified red cell pyrimidine 5'-nucleotidase (P5N) from a patient with P5N deficiency provided the evidence for a structural alteration of the enzyme protein. Red cell adenosine deaminase (ADA) from a patient with 40-fold increase in ADA activity associated with hemolytic anemia was purified and compared with that from normal subjects. It is most conceivable that the increased ADA activity represents increased amount of structurally normal enzyme.
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PMID:Studies on pyruvate kinase deficiency, pyrimidine 5-'nucleotidase deficiency and adenosine deaminase overproduction. 627 14


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