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:3.5.4.17 (adenosine deaminase)
5,206 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kinetic studies with adenylate deaminase have been performed by stopped flow methods at 20 degrees C in 0.01 M imidazole/HCl, pH 6.5. The data were analyzed using either the whole time course of the reaction or the initial portion of the full time course. At low KCl concentrations, activation by the product IMP complicates any interpretation. In the presence of 0.15 M KCl, the results are interpreted in terms of three types of purine nucleotide binding sites: an active site, an inhibitory site which appears to be relatively specific for nucleoside triphosphates, and an activating site which shows relatively little specificity for nucleoside phosphates. Nucleotide binding to the activating site weakens binding to the inhibitory site. Sigmoidal kinetic data observed as a function of AMP in the presence of the inhibitor GTP are interpreted in terms of AMP binding to the activating site and weakening GTP binding. A fragment of myosin, subfragement-2, which has previously been shown to form a tight complex with adenylate deaminase (Ashby, B., and Frieden, C. (1977) J. Biol. Chem. 252, 1869--1875) activates the deaminase reaction only slightly. Complex formation, however, makes the reaction less susceptible to inhibition by GTP, although high levels of this nucleotide will disrupt the complex. In the presence of GTP or GTP plus subfragment-2, hysteretic effects are observed.
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PMID:Adenylate deaminase. Kinetic and binding studies on the rabbit muscle enzyme. 72 7

Decrease in monoamine oxidase and increase in diamine oxidase and adenylate deaminating activities were found in rat liver mitochondrial fractions after repeated injections of ethanol. A monoamine oxidase inhibitor pargyline and an inhibitor of phosphodiesterase theophylline prevented the increase in adenylate deaminating activity in a subfraction of mitochondrial membranes in the ethanol intoxicated rats. In a subfraction of soluble mitochondrial proteins pargyline did not affect but theophylline prevented completely the increase in adenylate deaminating activity. The stimulation of adenylate deaminating activity in mitochondrial fractions of rat liver in ethanol intoxication might be caused by: 1) transformation of mitochondrial monoamine oxidases (in the subfraction of mitochondrial membranes) and 2) activation (or increased biosynthesis) of the adenylate deaminase in the subfraction of soluble mitochondrial proteins. The adenylate cyclase system is probably involved in the latter process.
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PMID:[Monoamine oxidase and adenylate deaminase activity of mitochondrial fractions of the rat liver in alcoholic intoxication]. 82 6

1. Theoretical considerations in continuous flow analysis by Walker, Shepherdson and McGowan have been applied to continuous flow radiorespirometry of 14C-glucoses to demonstrate ethanol response differences between water- and ethanol preferring mice. 2. Ethanol dosages in the n mols/kg range stimulated glucose utilization rates more in ethanol-than in water-preferring mice, while intermediate dosages (micron and low mmol/kg) produced equal stimulation but at different dosages. Pharmacological dosages (20-88 mmols/kg) inhibited glucose rates in water-preferring mice. The inhibition was released at 44 mmols/kg in ethanol-preferring mice. 3. Inhibition release was shown to be associated more with glucose carbons other than one, and considered consistent with a sodium-plus potassium-activated ATPase mechanism. 4. Intermediate ethanol dosage changes could be assigned to differences induced in glucose carbon one metabolism with H2O2-catalase and/or microsomal-ethanol-oxidizing systems (MEOS) mechanisms. 5. Our studies suggest that measurements of adenylate deaminase activities might clarify shifts in transaminations (human) and shifts in mononucleotides seen following chronic ethanol ingestion.
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PMID:Ethanol-host interactions determined by radiorespirometry of 14C glucoses. 86 81

The regulatory properties of adenylate deaminase (EC 3.5.4.6) from Ehrlich ascites tumor cells suggest that the reaction catalyzed by this enzyme serves to protect the cell against sharp decreases in the adenylate energy charge by removing adenosine 5'-monophosphate generated when the rate of utilization of adenosine triphosphate is suddenly increased. The enzyme is effectively inhibited under normal physiological conditions of high energy charge (0.9) and 4 to 5 mM adenine nucleotide pool size. The reaction is sharply activated by a decrease in the energy charge in the physiological range (0.9 to 0.6). At low energy charge (0.6), decrease in the size of the pool causes a marked and nonlinear decrease in the rate of the deaminase reaction. This effect presumably serves to prevent excessive depletion of the adenine nucleotide pool. Calculations based on the kinetic data obtained in this study show that the AMP deaminase reaction can account for the well-established alteration of adenine nucleotide metabolism that is observed following addition of glucose or 2-deoxyglucose to intact ascites cells.
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PMID:Role of the adenylate deaminase reaction in regulation of adenine nucleotide metabolism in Ehrlich ascites tumor cells. 94 36

1. Methods are described whereby the soleus muscle of the rat may be used for the investigation of initial processes in the absence of oxidative recovery. 2. The anaerobic conditions employed had no effect on the concentration of phosphocreatine in resting muscle or the mechanical response during contraction. 3. Muscles were stimulated tetanically for 10 s at 17-18 degrees C. Measurements were made of the heat production and metabolic changes that occurred during a 13 s period following the first stimulus. 4. There was no detectable change in the concentration of ATP. Neither was there detectable activity of adenylate kinase or adenylate deaminase. The changes in the concentration of glycolytic intermediaries were undetectable or very small. 5. The change in the concentration of phosphocreatine was large and amounted to -127 +/- 11-4 mumol/mmol Ct (mean and S.E. of the mean, negative sign indicates break-down, Ct = free creatine + phosphocreatine) which is equivalent to about -2-13 mumol/g wet weight of muscle. The heat production was 6549 +/- 408 mJ/mmol Ct (mean and S.E. of mean) which is equivalent to about 110 mJ/g. 6. About 30% of the observed energy output is unaccounted for by measured metabolic changes. 7. The ratio of heat production (corrected for small amounts of glycolytic activity) to phosphocreatine hydrolysis was -49-7 +/- 5-6 kJ/mol (mean and S.E. of mean), in agreement with previous results using comparable contractions of frog muscle, but different from the enthalpy change associated with phosphocreatine hydrolysis under in vivo conditions (-34 kJ/mol). 8. The results support the notion that the discrepancy between energy output and metabolism is an indication of an unidentified process of substantial energetic significance that is common to a number of species.
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PMID:Heat production and chemical change during isometric contraction of rat soleus muscle. 97 98

Short-chain aliphatic esters and amides of adenosine-5'-carboxylic acid caused marked increases in coronary sinus oxygen tension (PO2) in the dog; the amides were generally more potent, causing additionally marked hypotension and tachycardia. The hypotensive effect was observed also in the spontaneously hypertensive rat. That the increase in coronary sinus PO2 paralleled an increase in coronary flow was verified with ethyl adenosine-5'-carboxylate hydrochloride. This compound also increased the reactive hyperemic response. Aminophylline blocked the increase in coronary flow. A representative amide and ester were very poor substrates for adenosine and adenylate deaminase in vitro; the amide exhibited a weak inhibitor effect on the enzymic activities while the ester was inactive. The observations that the compounds (1) cause marked pharmacological effects within seconds after intravenous administration, (2) are blocked by aminophylline like adenosine, (3) are not deaminated significantly in vitro by either adenosine or adenylate deaminase, and (4) cannot be phosphorylated at the 5' terminus because the 5'-OH has been removed chemically, support the hypothesis that they are acting directly on an "adenosine receptor" and have a prolonged duration of action because they are not metabolized significantly by the normal physiological pathways of adenosine degradation.
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PMID:Cardiovascular effects of nucleoside analogs. 105 66

After a single intraperitoneal injection of serotonin into rats adenylate deaminase activity in the mitochondrial fraction of the liver was stimulated. The conditions under which a twofold increase in the deamination of AMP occurred, after serotonin administration,were determined. Preliminary blocking of monamine oxidase activity did not prevent this effect of serotonin.
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PMID:Stimulation of adenylate deaminase activity by serotonin. 111 59

Five enzymes concerned with the metabolism of adenine derivatives were assayed in seven regions of the rat brain. A region which included the hypothalamus had the highest AMP deaminase and adenosine deaminase activities, while its 5'-nucleotidase activities were relatively low. The enzymes named and also the uptake of [14C]adenine by incubated tissue samples were more active with hypothalamic than with neocortical tissues. On superfusion with glucose-bicarbonate saline after assimilating [14C]adenine, the hypothalamic tissues released about 0.2 per cent of their 14C content per minute. This release was increased fourfold with electrical excitation but the presence of 0.25 muM tetrodotoxin prevented most of this increase. The compounds released during superfusion and electrical stimulation were preponderantly hypoxanthine, inosine, and adenosine, with only small amounts of adenine nucleotides. The output of all these compounds increased during the period of stimulation and also the proportion of adenine nucleotides increased when stimulation was carried out in the presence of tetrodotoxin. The output of the nucleotides and adenosine increased more promptly when stimulated than did that of the other compounds named. The results are discussed in terms of the metabolic roles of the enzymes concerned. and in relation to whether the enzymes are acting on intracellular or extracellular substrates.
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PMID:The metabolism of adenine derivatives in different parts of the brain of the rat, and their release from hypothalamic preparations on excitation. 126 67

Subacute necrotizing encephalopathy (Leigh syndrome) is characterized by lactacidosis, seizures, ataxia, multiple cerebral hypervascularized lesions and mitochondrial oxidation defects. This is a report on a 21-year-old patient with proven Leigh syndrome, mild central and provokable peripheral lactacidosis, an extra-erythrocyte complex II defect, functionally reduced myokinase adenylate deaminase activity, but no ultrastructural mitochondrial changes. Determination of lactate, pyruvate and ammonia under ischemic conditions plus a pyruvate loading test were particularly useful. Oral flunarizine (Sibelium 30 mg/d) proved to be therapeutically effective.
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PMID:Diagnosis and treatment in a case of juvenile subacute necrotizing encephalopathy Leigh without cytochrome c oxidase deficiency. 132 78

1. The effects of a high-fat, high-energy diet and essential plus semi-essential amino acid gavage on pup rats have been studied (60-65 animals). 2. The activities of alanine transaminase, adenylate deaminase, glutamine synthetase and serine dehydratase have been tested in liver and muscle. 3. Plasma was used for the estimation of proteins, urea, amino acids, glucose, lactate, 3-hydroxybutyrate and acetoacetate. 4. Liver and muscle glutamine synthetase activities are increased by diet and gavage administered. Hepatic serine dehydratase is inhibited by a cafeteria diet but activated by amino acid gavage. Adenylate deaminase is inhibited by diet and gavage in the liver, but gavage does not affect this enzyme activity in muscle. Liver alanine transaminase is increased by the diet; in the muscle, cafeteria diet and amino acid gavage showed the highest values for this enzyme. 5. In the plasma, the increase in lactate produced by the diet is inhibited by the amino acids provided. Cafeteria-fed pups showed lower urea levels and higher 3-hydroxybutyrate concentrations in the plasma. 6. Intracellular glucose is diminished by cafeteria diet. In contrast, the blood cell amino acid concentration increases with diet and gavage supplied.
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PMID:Effect of diet and essential amino acids gavage on young rat amino acid metabolism enzymes. 136 2


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