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)

Deoxycoformycin-resistant rat hepatoma cells exhibit up to 300-fold increase in adenosine deaminase activity compared to the sensitive parental cells. In order to determine the basis of the increased enzyme activity in deoxycoformycin-resistant cells, adenosine deaminase was purified from rat liver and deoxycoformycin-sensitive and -resistant cells. Physical, kinetic, and immunological properties of the purified enzymes were compared. Purified adenosine deaminase from all sources was found to be a monomer with an Mr approximately 45,000. In addition, the purified enzymes had a similar isozyme pattern in nondenaturing polyacrylamide gels. Km values for adenosine and Ki values for deoxycoformycin did not differ among the purified enzymes. By double diffusion analysis and quantitative immunoprecipitation, the purified enzymes were found to be immunologically indistinguishable. These data indicate that deoxycoformycin-resistant rat hepatoma cells produce increased amounts of adenosine deaminase protein which results in increased enzymatic activity.
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PMID:Adenosine deaminase from deoxycoformycin-sensitive and -resistant rat hepatoma cells. Purification and characterization. 681 90

Adenosine deaminase was purified 3038-fold to apparent homogeneity from human leukaemic granulocytes by adenosine affinity chromatography. The purified enzyme has a specific activity of 486 mumol/min per mg of protein at 35 degrees C. It exhibits a single band when subjected to sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, non-denaturing polyacrylamide-gel electrophoresis and isoelectric focusing. The pI is 4.4. The enzyme is a monomeric protein of molecular weight 44000. Both electrophoretic behaviour and molecular weight differ from those of the low-molecular-weight adenosine deaminase purified from human erythrocytes. Its amino acid composition is reported. Tests with periodic acid-Schiff reagent for associated carbohydrate are negative. Of the large group of physiological compounds tested as potential effectors, none has a significant effect. The enzyme is specific for adenosine and deoxyadenosine, with Km values of 48 microM and 34 microM respectively. There are no significant differences in enzyme function on the two substrates. erythro-9-(2-Hydroxy non-3-yl) adenine is a competitive inhibitor, with Ki 15 nM. Deoxycoformycin inhibits deamination of both adenosine and deoxyadenosine, with an apparent Ki of 60-90 pM. A specific antibody was developed against the purified enzyme, and a sensitive radioimmunoassay for adenosine deaminase protein is described.
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PMID:Purification, characterization and radioimmunoassay of adenosine deaminase from human leukaemic granulocytes. 694 96

Deoxycoformycin, a tight-binding inhibitor of the enzyme adenosine deaminase, is a potent lymphocytotoxic agent. To examine the effect of deoxycoformycin on mouse tissues the drug was administered IP either by single or by repeated injections at one of two dose levels (0.2 or 10.0 mg/kg). Treatment with repeated injections at the higher dose caused retardation of growth and increases in lung and splenic mass. Body temperature, hematocrit, and total leukocyte count remained constant. Single injections at the lower dose caused complete inhibition of adenosine deaminase in liver and blood, and partial inhibition in jejunum and spleen, but at the higher dose complete inhibition of the enzyme in all tissues was obtained. Dosage appeared to have no effect on the rate of recovery of the deoxycoformycin-inhibited enzyme but marked tissue differences were observed. The enzymic activity recovered rapidly in jejunum (100% in 1 day) but slowly in other tissues (after 28 days, about 60% in spleen and liver; about 85% in kidney and blood, and 100% in lungs). These observations suggest that the recovery of inhibited enzyme depends largely upon the rate of proliferation of cells and protein synthesis. These tissue differences in recovery rates may play a role in the pharmacological and chemotherapeutic behavior of this drug.
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PMID:Deoxycoformycin toxicity in mice after long-term treatment. 697 Jun 29

2'-deoxycoformycin (2'-dCF; Pentostatin), a stoichiometric inhibitor of mammalian adenosine deaminase (ado deaminase), exhibits immunosuppressive and antilymphocytic activity in animal test systems. A clinical pharmacology/phase I study of 2'-dCF administered as a single agent has been completed (18 patients). Dose levels ranged from 0.1 mg/kg X 1 to 0.25 mg/kg/day X 5; ado deaminase and 2'-dCF were measured spectrophotometrically. Plasma decay curves were bi-exponential (alpha and beta t 1/2 values about 1 and 10 h respectively). Recovery of unchanged 2'-dCF from urine (48 h) was 32%--48% of the administered drug. Major toxic manifestations were lymphocytopenia (all patients) and urate nephropathy (1 patient, with subsequent patients in the series receiving allopurinol, 300 mg/day). Three partial responses were seen in seven patients with acute lymphocytic leukaemia receiving 0.25 mg 2'-dCF/kg/day X 5.
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PMID:The clinical pharmacology of the adenosine deaminase inhibitor 2'-deoxycoformycin. 697 Jun 30

2'-Deoxycoformycin (2'-dCF), a tight-binding inhibitor of adenosine deaminase, was administered to 26 pediatric patients with acute lymphoblastic leukemia in a Phase I study. Doses ranged from 0.25 to 1.0 mg/kg given i.v. for 3 consecutive days. Common toxicity included nausea, vomiting, diarrhea, hepatocellular enzyme elevations, and conjunctivitis. Lymphopenia occurred in all patients. The most serious adverse effects were acute tubular necrosis and central nervous system toxicity, which appeared to be dose related. In addition, two patients given the 0.75-mg/kg dose developed severe hepatic toxicity, although this could not be ascribed definitively to 2'-dCF. Antitumor activity was observed in eight patients, two of whom experienced a complete remission. Inhibition of lymphoblast adenosine deaminase activity was noted in the majority of cases and was observed at all doses. Antileukemic activity occurred at doses of 2'-dCF which were not associated with limiting toxicities. These results suggest that 2'-dCF is active against acute lymphoblastic leukemia and that a starting dose of 0.5 mg/kg/day be utilized in Phase II studies.
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PMID:Phase I study of 2'-deoxycoformycin in acute lymphoblastic leukemia. 697 90

Deoxycoformycin (DCF) is a tight-binding inhibitor of adenosine deaminase (ADA) currently undergoing phase I--II evaluation. Neurological toxicity has been a frequent and occasionally severe complication of treatment with this drug. A T-cell leukemia patient with an Ommaya reservoir was treated with DCF, and the pharmacokinetics of the drug in the cerebrospinal fluid and plasma were studied. DCF penetrates the cerebrospinal fluid and achieves levels as high as 1/10 the concurrent plasma levels. The accumulation of adenosine and deoxyadenosine in plasma, cerebrospinal fluid, and urine was monitored; the neuropharmacological effect of these metabolites is discussed.
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PMID:Deoxycoformycin: neurological toxicity. 697 88

2'-Deoxycoformycin (dCF), a potent inhibitor of adenosine deaminase, has recently undergone Phase I clinical trials and has been found to be therapeutically active in acute lymphoblastic leukemia. In this report, levels of dCF in plasma, plasma concentrations of adenosine and deoxyadenosine, and urine levels of deoxyadenosine were measured in leukemic patients undergoing treatment with dCF during a Phase I clinical trial. dCF was administered i.v. at a dose of 0.25 to 1.0 mg/kg (7.5 to 30 mg/sq m) for 3 consecutive days. Plasma drug levels of 2 to 6 microM were observed following the third dose of dCF, and drug accumulation occurred only at the 1-mg/kg dosage. In this limited series of patients, the plasma concentrations of adenosine and deoxyadenosine and the urine concentrations of deoxyadenosine did not show an obvious correlation with dCF dose, therapeutic response, or toxicity.
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PMID:Levels of 2'-deoxycoformycin, adenosine, and deoxyadenosine in patients with acute lymphoblastic leukemia. 697 54

The current status of three drugs of clinical interest to the National Cancer Institute is reviewed. m-AMSA, a drug with a wide spectrum of activity in murine tumors, is now in phase II trial and has shown itself to have a high order of activity in acute nonlymphocytic leukemia. Dihydroxyanthracenedione, a compound with some of the characteristics of anthracyclines but with no cardiac toxicity in animal toxicology studies, is in phase I evaluation. Deoxycoformycin, an adenosine analog which is a potent inhibitor of adenosine deaminase, has shown moderate activity in acute leukemia patients in phase I trials, and has the potential to produce synergistic antitumor toxicity when used with arabinofuranosyladenine.
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PMID:Current status of clinical trials of m-AMSA, dihydroxyanthracenedione, and deoxycoformycin. 697 70

A flow-limited physiologic mathematical model has been developed to describe the time course of 2'deoxycoformycin (2'dCF) concentrations in the plasma and tissues of mice following iv and ip doses. Urinary excretion is modeled as a linear involving filtration and secretion, since kidney clearance exceeded estimated glomerular filtration rate. Intracellular binding is described as the sum of linear nonspecific binding plus strong saturable binding to adenosine deaminase. Pharmacokinetic parameters are determined by a sequential optimization scheme in which each tissue is studied by means of a hybrid model. The model has been used to predict pharmacokinetic behaviour of 2'dCF in both normal and leukemic mice, and model simulations are compared with published data.
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PMID:Physiologic model for the pharmacokinetics of 2'deoxycoformycin in normal and leukemic mice. 697 36

2'-Deoxycoformycin (DCF) is an inhibitor of the enzyme adenosine deaminase (ADA) and has shown promise as an antileukemia agent. For the assessment of the extent to which systemically administered DCF crosses into the central nervous system (CNS), rhesus monkeys were given iv boluses of DCF. Simultaneous blood and cerebrospinal fluid (CSF) samples were assayed for DCF levels at times ranging from 10 minutes to 6 hours after the drug was given. Average peak CSF drug levels of 5.5 X 10(-8) M and 3 X 10(-7) M were reached 1 1/2 - 2 hours following injections of 0.25 and 1.0 mg DCF/kg, respectively. The ratio of peak CSF to simultaneous plasma levels was 1 to 10. Data obtained from a patient who had acute lymphocytic leukemia and who was given iv DCF were comparable. Drug levels achieved within the CSF following iv administration of 0.25 mg DCF/kg are similar to those previously demonstrated to inhibit ADA. These results may be important both for understanding DCF-related CNS toxicity and for designing combination chemotherapy with DCF.
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PMID:Cerebrospinal fluid levels of 2'-deoxycoformycin after systemic administration in monkeys. 697 72


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