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:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With N-methylhydantoin (NMH) as the main organic substrate, two strictly anaerobic spore forming Gram-positive bacterial strains were isolated from sewage sludge. These strains, named Clostridium sp. FS23 and Clostridium sp. FS41, totally degraded NMH, via N-carbamoylsarcosine (CS) and sarcosine as intermediates. Strain FS23 grew also with creatinine, which was converted to NMH by creatinine iminohydrolase (EC 3.5.4.21). This enzyme was formed at high rates with all substrates tested. Cytosine and 5-fluorocytosine were not utilized as substrates by creatinine iminohydrolase preparations purified to a homogeneity of 98%. NMH amidohydrolase (NMHase) and N-carbamoylsarcosine amidohydrolase (CSHase) turned out to be inducible in both strains. Other than in aerobic organisms, NMHase from these two isolated did not require ATP for enzymatic activity. SH-group protecting agents were not necessary for stability.
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PMID:Creatinine and N-methylhydantoin degradation in two newly isolated Clostridium species. 151 May 64

The contribution of 5'-nucleotidase and AMP-deaminase to adenine nucleotide degradation in human cardiomyocytes isolated from diseased or normal heart was investigated. The preparation used contained 30 to 50% of viable cells and the nucleotide degradation was stimulated by addition of deoxyglucose and oligomycin. To distinguish pathways of nucleotide degradation, adenosine deaminase was inhibited by erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA). Under these conditions, ATP concentration was decreased by 60% after 45 min of incubation. Simultaneously, increases in intra- and extracellular catabolite concentrations have been observed. Adenosine was the predominant catabolite found in both the cells and in the extracellular medium accounting for more than 70% of all degradation products. Intracellular adenosine concentration rose to 300 times greater than that outside the cell. An increase in intra- and extracellular inosine was also seen. Only a small increase of IMP concentration was observed. No hypoxanthine accumulation was found. No significant change in initial adenine nucleotide concentrations were observed in isolated cells during aerobic incubation without deoxyglucose and oligomycin. In conclusion, a pathway involving adenosine production appears to be the principal route of nucleotide degradation in human cardiomyocytes.
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PMID:Adenine nucleotide catabolism and adenosine formation in isolated human cardiomyocytes. 156 34

AMP-deaminase from human kidney (cortex and medulla) was purified and the physicochemical properties were characterized. The enzyme from both portions of the kidney exhibited identical kinetics and regulatory properties. At optimal pH (6.6), the AMP-deaminase studied exhibited a distinctly sigmoidal substrate saturation kinetics, with the half-saturation parameter (S0.5) as high as 10 mM. ATP at 1 mM strongly activated the enzyme, decreasing S0.5 nearly 10-fold. The activating effect of ADP was less strong. Orthophosphate inhibited the enzyme, but the inhibition observed was weak (Ki approximately 16 mM) and had a pure competitive character. At pH 7.2, physiological for the kidney cortex, orthophosphate inhibition became even weaker and became partially competitive. Variations in the adenylate energy charge had potent effects on the activity of AMP-deaminase, depending on the size of the total adenine nucleotide pool examined. The results of gel filtration and SDS-PAGE indicated that human kidney AMP-deaminase is an oligomeric enzyme composed of four, probably identical, subunits weighing about 37 kDa each.
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PMID:Purification and properties of AMP-deaminase from human kidney. 162 54

Under the effects of 0.7 MPa of oxygen leading to a convulsive state, AMP-deaminase activity increased significantly in the rat brain mitochondrial fraction with only a tendency to increase in cytoplasmic fraction. Stimulated effects of the enzyme allosteric activator ATP is more obvious in intact animals than in hyperoxic ones. Pretreatment with AMP before hyperoxygenation exerts a protective effect preventing the alteration of monoamine oxydase catalytic properties, stabilizing membrane structure and improving the general state of the animals.
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PMID:[AMP deaminase activity in hyperoxia and the effect of AMP on animal sensitivity to oxygen under pressure]. 165 22

An RNA helicase, isolated from nuclear extracts of HeLa cells, displaced duplex RNA in the presence of any one of the eight common nucleoside triphosphates. The unwinding reaction was supported most efficiently by ATP and GTP and poorly by dCTP and dTTP. The enzyme activity, purified 300-fold, contained two major protein bands of 80 and 55 kDa when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All fractions that contained RNA helicase activity also possessed single-stranded RNA-dependent nucleoside triphosphatase activity. Purified RNA helicase fractions displaced a hybrid of U4/U6 RNAs with the same efficiency as it displaced other duplex RNA structures. In contrast, the RNA helicase did not displace duplex RNA/DNA and DNA/DNA structures. Evidence is presented that suggests that this RNA helicase can displace duplex RNA by translocating in both the 3' to 5' and the 5' to 3' directions. The properties of the RNA helicase described here differ from the deaminase RNA unwinding activity described in Xenopus oocytes (Bass, B.L., and Weintraub, H. (1987) Cell 48, 607-613) and from the p68 HeLa RNA helicase (Hirling, H., Scheffner, M., Restle, T., and Stahl, H. (1989) Nature 339, 562-564).
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PMID:The isolation and characterization of an RNA helicase from nuclear extracts of HeLa cells. 170 30

The effects of prolonged ischaemia and subsequent reperfusion during and after reconstructive microsurgery on energy metabolism were studied. Repeated skeletal muscle biopsies were taken and analysed for high energy phosphates and their degradation products by high performance liquid chromatography and for lactate by a fluorometric procedure. Moderate changes in adenine nucleotides occurred during the first 4 h of ischaemia. After 6 h of ischaemia, when the creatine phosphate store was almost depleted and the lactate level had increased to 111 mmol kg-1 dry muscle, ATP content decreased and inosine monophosphate started to accumulate. The inosine monophosphate accumulation was however small, in spite of a high lactate level, which suggests that the increase in H+ associated with lactate formation is not important for the activation of AMP-deaminase during the present conditions. In spite of the accelerating metabolic deterioration during the later period of ischaemia, the reperfusion of the muscle resulted in a rapid normalization of all the studied metabolites, thereby indicating a rapid restoration of the muscle energy stores.
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PMID:Small accumulation of inosine monophosphate (IMP) despite high lactate levels in latissimus dorsi during transplantation. 191 40

AMP-deaminase from human uterine smooth muscle has been isolated, and properties of the enzyme were characterized. At pH 7.0, and in the presence of 100 mM potassium chloride the enzyme manifests a distinctly sigmoidal type of kinetics, with S0.5 parameter value about 12 mM. 1 mM ATP strongly activates the enzyme, and diminishes the value of S0.5 to 1.2 mM. In contrast to that 2.5 mM orthophosphate slightly inhibits the activity of AMP-deaminase studied and increases the S0.5 to about 14 mM. Similarly to ATP, orthophosphate does not influence the maximum velocity of the reaction. Electrophoresis in the presence of sodium dodecyl sulphate revealed that the molecular weight of human smooth muscle AMP-deaminase subunit is close to 37 kDa.
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PMID:Purification and properties of AMP-deaminase from human uterine smooth muscle. 201 70

The effect of adenosine (ADO) on the recovery of cellular adenine nucleotides (AN) was evaluated in the cultured cells deprived of oxygen and substrates (ischemia) and in nonischemic cells (control). The primary cultured cells were obtained from microdissected rabbit proximal straight tubules. Ten-day-old cultured cells were made ischemic for 6 hr, and allowed to recover for 24 hr. At the end of ischemia, cells were incubated with ADO, theophylline (T), dipyridamole (D), coformycin (C) or combined agents for 3 hr. Total AN (TAN) were determined after 3 and 24 hr of recovery. The results, after 3 hr of incubation, suggest that in both control and ischemic cells, ADO is taken up by cultured cells and is preferentially converted to nucleotides. This effect is blocked by D, which inhibits ADO uptake, uninfluenced by C, which inhibits ADO deaminase and potentiated by T, which inhibits 5'-nucleotidase. After 24 hr of recovery, the beneficial effects of ADO alone or combined D, C, or T, on TAN were not seen in control cells. In contrast, in the ischemic cells, after 24 hr of recovery, ADO + T normalized ATP, ADP and TAN to the preischemic levels. T alone significantly increased ATP after 24 hr of recovery. To demonstrate further that the beneficial effect of T is due to inhibition of 5'-nucleotidase, cells were treated with adenosine alpha, beta-methylene diphosphate in the same manner as T. Combined ADO + adenosine alpha, beta-methylene diphosphate normalized ATP, ADP and TAN after 24 hr of recovery. This finding suggests that inhibition of 5'-nucleotidase improves postischemic AN.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Roles of adenosine and theophylline on the recovery of adenine nucleotides in postischemic cultured renal tubular cells. 203 18

At pH 7.0 and physiological concentrations of the main regulatory ligands (ATP, ADP, orthophosphate), human uterine muscle AMP-deaminase follows a hyperbolic type of saturation kinetics with S0.5 parameter value about 2 mM. The enzyme is regulated by adenylate energy charge (AEC) variations, being the most active at the AEC value 0.5-0.6 or 0.5-0.7, depending on the size of the total adenine nucleotide pool. Long-chain acyl-CoA strongly inhibit activity of the enzyme, influencing mainly the maximum velocity of the reaction.
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PMID:Purification and properties of AMP-deaminase from human uterine smooth muscle. Regulation by adenylate energy charge and activated fatty acids. 206 99

The amidase activity of human alpha-thrombin has been studied in the presence of the adenosine nucleotides AMP, ADP and ATP. At low concentrations, adenosine nucleotides increase thrombin activity up to 30%, while at high concentrations (greater than 5 mM) inhibition takes place up to 20%. Inhibition is progressively reduced by increasing substrate concentration. A simple, phenomenological description of the linkage between adenosine nucleotide binding and amidase activity of human alpha-thrombin is proposed and the free energy changes for the underlying reactions involved in the linkage scheme are resolved by global analysis of the experimental data. The linkage scheme assumes that thrombin activation is determined by a conformational transition due to binding of adenosine nucleotides to a regulatory site. Inhibition, on the other hand, would be a consequence of competitive binding to the catalytic site.
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PMID:The linkage between adenosine nucleotide binding and amidase activity in human alpha-thrombin. 220 77


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