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)

Absence of AMP-deaminase was demonstrated by histochemical and biochemical methods in a muscle biopsy of a 25-year-old woman with facial and limb girdle myopathy. Venous ammonia failed to rise after ischaemic exercise. This patient further contributes to the variety of clinical pictures associated with AMP-deaminase deficiency. Whereas AMP-deaminase has been shown to play an essential role in the regulation of adenine nucleotide metabolism in the liver, its physiological function in muscle remains uncertain.
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PMID:Myoadenylate deaminase deficiency in a patient with facial and limb girdle myopathy. 616 80

Effects in vitro of glutamate, aspartate, fumarate and malate on substrate activation kinetics of AMP-deaminase in denervated and contralateral gastrocnemius muscles of the frog, Rana hexadactyla were studied. Glutamate increase the enzyme activity of both muscles by increasing maximal velocity (V) and decreasing Michaelis-Menten constant (Km), whereas, aspartate did not show any significant effect. Fumarate and malate exerted mixed type of inhibition by decreasing V and increasing Km of enzymes in both muscle preparations. The inhibitor constant (Ki) values suggest that the denervated muscle enzyme was more sensitive to fumarate and malate as compared to the contralateral muscle enzyme.
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PMID:Effects of some metabolic intermediates on AMP-deaminase activity in denervation atrophy. 618 33

A methodology is presented for systemic analysis of purine enzymes in small lymphocyte subfractions. For the determination of 7 different enzymes of purine metabolism *hypoxanthine-guanine phosphoribosyltransferase (HG-PRT), adenine phosphoribosyltransferase (A-PRT), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), 5'-nucleotidase (5'N), and AMP-deaminase) less than 200,000 peripheral blood lymphocytes are needed. 1000-6000 lyophilised lymphocytes are incubated in micro-incubation vessels (3 microliter) with radioactive substrates for 15-180 min. Separation of substrates and products is achieved by thin-layer chromatography on PEI-cellulose. Addition of BSA to the incubation mixtures results in higher specific enzyme activities and narrower ranges of mean values of a control group.
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PMID:Enzymes of purine nucleotide metabolism in human lymphocytes. 625 89

Cyclic AMP and folic acid act as chemotactic factors in Dictyostelium discoideum. Both agents, when applied extracellularly, also control cell development from the growth stage to the acquisition of aggregation competence. Cyclic AMP phosphodiesterase and folate deaminase are extracellular enzymes whose activity is regulated during early differentiation of D. discoideum cells. The two enzymes help control the extracellular levels of cyclic AMP and folic acid. The substrates cyclic AMP and folic acid each increase the extracellular activity of folate deaminase as well as phosphodiesterase. The specificity of extracellular phosphodiesterase regulation by cyclic AMP indicates that the effect is mediated by specific cyclic AMP receptors rather than the catalytic site of cell surface phosphodiesterase. To some extent cyclic AMP and folic acid are interchangeable with respect to regulating differentiation and enhancing enzymatic inactivation of intercellular signals. Thus the two extracellular signals may share a common cellular pathway of signal transduction. The regulation of folate deaminase and phosphodiesterase by folic acid does not always parallel the folic acid effects on development. Pulses of folic acid stimulate development of aggregation competence, whereas a continuous flux inhibits. In contrast, either continuous flux or pulses of folic acid increase the deaminase and phosphodiesterase activities.
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PMID:Folate deaminase and cyclic AMP phosphodiesterase in Dictyostelium discoideum: their regulation by extracellular cyclic AMP and folic acid. 626 63

5'-Nucleotidase, adenosine phosphorylase, adenosine deaminase and purine nucleoside phosphorylase, four enzymes involved in the utilization of exogenous compounds in Bacillus cereus, were measured in extracts of this organism grown in different conditions. It was found that adenosine deaminase is inducible by addition of adenine derivatives to the growth medium, and purine, nucleoside phosphorylase by metabolizable purine and pyrimidine ribonucleosides. Adenosine deaminase is repressed by inosine, while both enzymes are repressed by glucose. Evidence is presented that during growth of B. cereus in the presence of AMP, the concerted action of 5'-nucleotidase and adenosine phosphorylase, two constitutive enzymes, leads to formation of adenine, and thereby to induction of adenosine deaminase. The ionsine formed would then cause induction of the purine nucleoside phosphorylase and repression of the deaminase. Taken together with our previous findings showing that purine nucleoside phosphorylase of B. cereus acts as a translocase of the ribose moiety of inosine inside the cell (Mura, U., Sgarrella, F. and Ipata, P.L. (1978) J. Biol Chem. 253, 7905-7909), our results provide a clear picture of the molecular events leading to the utilization of the sugar moiety of exogenous AMP, adenosine and inosine as an energy source.
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PMID:Induction and repression of enzymes involved in exogenous purine compound utilization of Bacillus cereus. 627 19

The inhibitory effects of adenosine, ATP, 5'-adenylyl methylene diphosphonate (beta, gamma-meATP) and adenosine 5'-alpha, beta-methylene triphosphonate (alpha, beta-meATP) were compared on the cholinergic twitch responses to transmural stimulation of the guinea-pig ileum. Adenosine, ATP and beta, gamma-meATP reduced the twitch responses in a concentration dependent manner. Theophylline antagonized and dipyridamole potentiated the inhibitory responses to adenosine, ATP and beta, gamma-meATP. Inhibitory responses to alpha, beta-meATP were usually preceded by an enhancement in twitch height. Contractions of the unstimulated ileum to alpha, beta-meATP were blocked by atropine and tetrodotoxin while those elicited by ATP were unaffected, which suggests that the initial excitatory effects of alpha, beta-meATP may be due to its ability to release ACh from cholinergic nerve terminals. Use of high pressure liquid chromatography and bioluminescence assay techniques demonstrated the ability of the tissue to degrade ATP and beta, gamma-meATP and, at a much slower rate, alpha, beta-meATP. Inhibitory responses to ATP, AMP and beta, gamma-meATP were reduced by adenosine deaminase, which also abolished responses to adenosine. 5'-AMP deaminase abolished responses to AMP and adenosine, and reduced those to ATP and beta, gamma-meATP. The results suggest that the inhibitory effect of ATP on cholinergic neurotransmission is due to its rapid breakdown to AMP or adenosine, which act on prejunctional P1-purinoceptors.
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PMID:Evidence for the presence of P1-purinoceptors on cholinergic nerve terminals in the guinea-pig ileum. 627 50

Studies of the folate chemotactic receptor of vegetative Dictyostelium discoideum cells have been hampered by the presence of the degradative enzyme folate deaminase. The diaminopterin compounds aminopterin and methotrexate (MTX) are chemoattractants but are not attacked by the deaminase. [3',5',7,9-3H]methotrexate ([3H]MTX) is a nondegraded radioligand for the folate receptor. Binding to the receptor is rapid, reaching steady state in less than one min, and reversible in less than 15 s by an excess of unlabeled MTX. A single class of binding sites is found with a Kd of 2 x 10(-8) M, which correlates well with the concentration dependence of chemotaxis. Folate, aminopterin, and MTX all compete for [3H]MTX binding, whereas pterin, p-aminobenzoate, and nucleotides do not. Analysis of the receptor during differentiation indicates a decrease in site number by a factor of 3 with no change in affinity during the first 7 hr. During this time, the directional response (chemotaxis) to MTX and folate is lost, but a nondirectional stimulation of motility rate (chemokinesis) is retained. The response to cyclic AMP displays reciprocal behavior, first appearing as a chemokinetic response and then as a chemotactic response.
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PMID:[3H]Methotrexate as a ligand for the folate receptor of Dictyostelium discoideum. 627 68

Enzymatic activities that catalyze the interconversion of purines and purine derivatives were detected in cell extracts of Spirochaeta aurantia, Spirochaeta stenostrepta, Treponema succinifaciens, and Treponema denticola. Phosphoribosyltransferase activities present in cell extracts of each of the four spirochete species functioned in the conversion of adenine, hypoxanthine, and guanine to AMP, IMP, and GMP, respectively. Nucleotidase activities in the extracts mediated the formation of nucleosides from nucleotides. The conversion of adenosine, inosine, and guanosine to the respective purine bases was catalyzed by nucleoside phosphorylase and, in some instances, by nucleoside hydrolase activities. Guanine deaminase activity was found in both S. aurantia and S. stenostrepta, whereas adenosine deaminase activity was detected only in S. aurantia. Adenine deaminase activity in T. succinifaciens extracts was sensitive to O2 and was relatively resistant to heating. Our results indicate that the four species of spirochetes studied possess a broad spectrum of purine interconversion enzymes. It is suggested that these enzymes may function in metabolic processes important for the survival of spirochetes in nutrient-poor natural environments.
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PMID:Enzymatic activities for interconversion of purines in spirochetes. 629 62

Membrane-bound 3'.5'-cyclic nucleotide phosphodiesterase (EC 3.1.4.17) is closely associated physically with nucleotidase and deaminase, thus forming an enzyme cluster of unique catalytic behaviour [H. Wombacher, Archs. Biochem. Biophys. 201, 8 (1980)]. This multienzyme cluster, which was found in the microsomal fraction of beef adrenal cortex, catalyses the degradation of cyclic AMP, via AMP and adenosine, to inosine. The present study shows how theophylline, a well-known inhibitor of the phosphodiesterase, acts on the membrane-bound multienzyme sequence. The findings were as follows. Firstly, as expected, theophylline inhibited the phosphodiesterase competitively. In particular, the high-affinity enzyme was inhibited by mM concentrations of theophylline. Phosphodiesterase activity was tentatively ascribed to two enzymes, one with a low Km [0.3 microM], one with a high Km [60 microM]. Secondly, theophylline inhibited the nucleotidase activity to a great extent. A detailed kinetic analysis showed the inhibition to be hyperbolic noncompetitive (alpha = 1, beta = 0.35 and Ki = 0.25 mM). Thirdly, theophylline did not inhibit the deaminase activity of the multienzyme sequence. A model of theophylline inhibition is suggested explaining how an effector could modulate the kinetic behaviour of an enzyme cluster by acting at a single allosteric site. Finally, in view of the existence of the cyclic AMP degrading multienzyme sequence and the effect of theophylline on it, the possibility is discussed that physiologically active adenosine is derived from cyclic AMP.
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PMID:Theophylline effect on the cyclic AMP degrading multienzyme sequence. 629 12

The effects of degradative enzymes and enzyme inhibitors were examined on the inhibitory actions of adenosine, AMP and ATP on atrial muscle and on the cholinergic responses of the ileum to transmural stimulation of the guinea-pig, in order to determine whether ATP responses are mediated by its breakdown products, AMP and adenosine. In both the atria and the ileum, adenosine deaminase reduced responses to ATP, although when combined with 5'-nucleotidase it had no further effect. In the atrium, the 5'-nucleotidase inhibitor, alpha,beta-methylene ADP (APCP), had no effect on its own, but prevented the potentiating effect of the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) on responses to ATP. In the ileum, EHNA had no effect, but APCP potentiated responses to ATP. The enzyme 5'-AMP deaminase was shown to have a non-specific inhibitory effect on purine responses in both preparations. It is concluded for both preparations, that (1) the inhibitory responses to ATP are partly mediated by AMP and adenosine following the ectoenzymatic breakdown of ATP, and partly mediated by ATP itself, and (2) that AMP as well as adenosine can act directly on P1-purinoceptors. It is suggested that of the two breakdown products of ATP, AMP and adenosine, a larger proportion of the response is mediated by AMP in the ileum, whereas adenosine is the major mediator in the atrium.
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PMID:Stimulation of P1-purinoceptors by ATP depends partly on its conversion to AMP and adenosine and partly on direct action. 632 Dec 10


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