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:3.5.4.6 (AMP deaminase)
690 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several methods for removing interfering nucleotides, adenosine-5'-monophosphate and adenosine 5'-triphosphate from brain extracts have been studied. An enzymic method, using adenylic acid deaminase, has been found suitable. This deaminates adenosine monophosphate to 5'-inosinic acid, an inactive compound which does not influence the estimations of substance P. Owing to the adenosine triphosphatase content of the enzyme extract, adenosine triphosphate was also inactivated. For the estimation of adenosine monophosphate-deaminase activity, a simple colorimetric method is described which measures the ammonia liberated from adenosine monophosphate. Substance P in mouse brain extracts was estimated after treatment of the animals with various drugs, and after the enzymic removal of interfering nucleotides from the brain extracts. The drugs had no effect on the substance P content of mouse brain. The effect of drugs on the contractions of the guinea-pig ileum induced by substance P was also investigated, and the effect of drugs on the estimations of substance P in brain extracts is discussed.
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PMID:REMOVAL OF INTERFERING NUCLEOTIDES FROM BRAIN EXTRACTS CONTAINING SUBSTANCE P. EFFECT OF DRUGS ON BRAIN CONCENTRATIONS OF SUBSTANCE P. 1406 36

AMP-deaminase (EC 3.5.4.6) is an enzyme of nucleotide breakdown involved in regulation of adenine nucleotide pool in mammalian cells. Reaction catalysed by AMP-deaminase constitutes a rate-limiting step in adenine nucleotide catabolism in liver. In this study kinetic and regulatory properties of AMP-deaminase purified from normal and cirrhotic human liver were investigated. In comparison to AMP-deaminase extracted from the normal human liver, AMP-deaminase extracted from the cirrhotic liver was less sensitive towards substrate analogues, and only a very limited response towards pH and adenylate energy charge changes tested for enzyme isolated from this tissue source had been observed. At physiological pH 7.0, in the absence and in the presence of important allosteric effectors (ATP, ADP, GTP and orthophosphate), AMP-deaminases from the two sources studied manifested different regulatory profiles, with half-saturation constant (S0.5) values being distinctly higher for the enzyme extracted from the pathological organ. In contrast to AMP-deaminase isolated from the normal, healthy liver, where presence of relatively large (68 kDa) protein fragment was also detected, only smaller protein fragments were identified, while SDS-PAG electrophoresis of AMP-deaminase isolated from the cirrhotic liver was performed. The obtained results indicate clearly that advanced proteolytic processes occurring in the cirrhotic liver may affect structural integrity of AMP-deaminase studied, making enzyme less active and less sensitive to regulatory action of important allosteric effectors.
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PMID:AMP-deaminase from normal and cirrhotic human liver: a comparative study. 1553 16

Blood lymphocyte activities of 5'-nucleotidases, adenosine deaminase and AMP deaminase have been investigated for evaluation of immune system state of albino rats under normal conditions, immobilization stress and effect of radiation. Stress-induced reactions were characterized by changes of activities of these enzymes. However the ratios of activities 5'- nucleotidase/AMP-deaminase (coefficient A) and adenosine-deaminase/AMP-deaminase (coefficient B) were even more informative than separate analysis of these enzymes.
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PMID:[Enzymes of purine nucleotide metabolism in assessment of the functional competence of the immune system]. 1594 54

Adenosine deaminase (ADA) is a well-characterized enzyme involved in the depletion of adenosine levels. A group of proteins with similarity to ADA, the adenosine deaminase-related growth factors (ADGF; known as CECR1 in vertebrates), has been described recently in various organisms. We have determined the phylogenetic relationships of various gene products with significant amino acid similarity to ADA using parsimony and Bayesian methods, and discovered a novel paralogue, termed ADA-like (ADAL). The ADGF proteins share a novel amino acid motif, "MPKG," within which the proline and lysine residues are also conserved in the ADAL and ADA subfamilies. The significance of this new domain is unknown, but it is located just upstream of two ADA catalytic residues, of which all eight are conserved among the ADGF and ADAL proteins. This conservation suggests that ADGF and ADAL may share the same catalytic function as ADA, which has been proven for some ADGF members. These analyses also revealed that some genes previously thought to be classic ADAs are instead ADAL or ADGFs. We here define the ADGF, ADAL, ADA, adenine deaminase (ADE), and AMP deaminase (AMPD) groups as subfamilies of the adenyl-deaminase family. The availability of genomic data for the members of this family allowed us to reconstruct the intron evolution within the phylogeny and strengthen the introns-late hypothesis of the synthetic introns theory. This study shows that ADA activity is clearly more complex than once thought, perhaps involving a delicately balanced pattern of temporal and spatial expression of a number of paralogous proteins.
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PMID:Phylogenetic analysis reveals a novel protein family closely related to adenosine deaminase. 1624 11

AMP-deaminase (AMP-aminohydrolase, EC 3.5.4.6), a highly regulated oligomeric enzyme catalyzing the irreversible deamination of adenylic acid (5'-AMP), is located at a branch point of adenylate nucleotide catabolism. It plays an important role in the stabilization of adenylate energy charge (AEC) and the regulation of the purine nucleotide pool in several types of animal tissue. Tissue- and stage-specific isoforms of AMP-deaminase were described in mammals. In humans, three isozymes of AMP-deaminase, i.e. M (muscle), L (liver), and E (erythrocyte), exhibiting different physical, catalytic, and regulatory properties, were identified. AMP-deaminase activity is encoded by a multigene family in which two genes produce at least three mRNAs through alternative splicing of one of the primary transcripts. In this study we present all found and so far unpublished detailed knowledge about AMP-deaminase gene structures. We also present basic information on the effects of these gene mutations.
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PMID:[Family of AMP-deaminase genes]. 1625 16

Embryonic factor 1 (FAC1) is one of the earliest expressed plant genes and encodes an AMP deaminase (AMPD), which is also an identified herbicide target. This report identifies an N-terminal transmembrane domain in Arabidopsis FAC1, explores subcellular fractionation, and presents a 3.3-A globular catalytic domain x-ray crystal structure with a bound herbicide-based transition state inhibitor that provides the first glimpse of a complete AMPD active site. FAC1 contains an (alpha/beta)(8)-barrel characterized by loops in place of strands 5 and 6 that places it in a small subset of the amidohydrolase superfamily with imperfect folds. Unlike tetrameric animal orthologs, FAC1 is a dimer and each subunit contains an exposed Walker A motif that may be involved in the dramatic combined K(m) (25-80-fold lower) and V(max) (5-6-fold higher) activation by ATP. Normal mode analysis predicts a hinge motion that flattens basic surfaces on each monomer that flank the dimer interface, which suggests a reversible association between the FAC1 globular catalytic domain and intracellular membranes, with N-terminal transmembrane and disordered linker regions serving as the anchor and attachment to the globular catalytic domain, respectively.
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PMID:Membrane association, mechanism of action, and structure of Arabidopsis embryonic factor 1 (FAC1). 1654 43

AMP-deaminase (EC 3.5.4.6) is an enzyme responsible for stabilising adenylate energy changes. The properties of this enzyme are controlled by various ligands of hydrophobic nature. An investigation of enzyme activity alterations under the influence of natural phenolic acids (tannic, ellagic and gallic) which are soluble in water, could evidence the biological toxicity of these compounds. In our study purified AMP-deaminase isolated from white muscle of Cyprinus carpio was exposed to phenolic acids in the concentration range of 1 to 50 microM as well as to tannic acid in the presence of Cu2+ ions (5 microM). On the basis of the obtained results we can conclude that among the tested acids, gallic acid did not contribute to the change in AMP-deaminase activity, whereas ellagic acid diminished its activity at the highest concentration (50 microM). Tannic acid caused a significant decrease in the enzyme activity in comparison to control for all used concentrations. Cu2+ ions alone reduced the activity of AMP-deaminase for all studied concentrations. A combined action of a chosen Cu2+ ions concentration (5 microM) with tannic acid at the concentration higher than 2 microM resulted in a decrease in the enzyme activity, but for lower tannic acid concentration of 1 microM the activity of AMP-deaminase was stimulated. These experiments showed that tannic acid may stop free radical chain reactions only at low concentrations (1 microM) in the presence of Cu2+ ions (5 microM).
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PMID:In vitro study of AMP-deaminase from fish (Cyprinus carpio) treated with hydrolyzable tannins. 1664 24

Background AMP-deaminase (EC 3.5.4.6) and 5'-nucleotidase (EC 3.1.3.5) are enzymes responsible for the maintenance of cellular adenine nucleotides pool. Both exist in several isoforms that differ in kinetic properties and tissue distribution. Profile of isoforms of these enzymes in human placenta has not been analyzed so far while this could be important for understanding of pathology of placental ischemia such as in preeclampsia. Our aim was therefore to analyze expression of AMPD and CN-I genes in human term placenta. Methods RT-PCR analysis was used for determine expression of AMPD1, AMPD2, AMPD3 and CN-I. Results and conclusion The experimental results presented here indicate that genes coding "AMP-preferring", cytosolic isozyme of 5'-nucleotidase (cN-I) as well as "muscle-type" isozyme of AMP-deaminase (AMPD1) are not expressed in human term placenta. Among other AMPD family genes, only these coding "liver-type" isozyme (AMPD2) and, in lesser degree, "erythrocyte-type" isozyme (AMPD3) of AMP-deaminase are expressed in this organ. The expression level of AMPD3 was a half of that presented by AMPD2. We conclude that high abundance of AMP-deaminase 2 transcript suggest that this particular isoform is a predominant pathway of adenine nucleotides degradation in human term placenta that follows liver-type regulation of this process.
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PMID:Expression patterns of AMP-deaminase and cytosolic 5'-nucleotidase genes in human term placenta. 1816 23

AMP-deaminase (AMPD, EC 3.5.4.6), which catalyzes the irreversible hydrolytic deamination of AMP to IMP and ammonia, is an important energy-related enzyme. The partial genomic sequence of the gene encoding myoadenylate deaminase (AMPD1) from the teleost fish Platichthys flesus was determined. The amino acid sequence of P. flesus AMPD1 shows 82% homology with that of the teleost fish Danio rerio. Comparison of genomic sequences of P. flesus and Rattus norvegicus reveals a high degree of conservation of both sequence and structural organization. A phylogenetic analysis of AMPD sequences shows that bony fish and mammalian AMPD1s arise by duplication of a common primordial gene.
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PMID:Partial characterization of the gene encoding myoadenylate deaminase from the teleost fish Platichthys flesus. 1982 Nov 38

Cytosolic enzymes AMP deaminase and adenosine deaminase (ADA) catalyze AMP and adenosine deamination, constitute rate-limiting steps of adenine nucleotide catabolism and play important roles in cellular energy metabolism. In this study, AMP deaminase and ADA activities of rat liver, neocortex, cerebellum, striatum and hippocampus were investigated in acute ammonia intoxication and subacute CCl(4)-induced hepatitis. Activities of both AMP deaminase and ADA in the liver were elevated by 2.4-4.2-fold (p<0.0001) in both models of hepatotoxic injury as compared with controls. In acute hyperammonemia activities of AMP, deaminase and ADA increased by 46-59% (p<0.02) in the neocortex and did not change in the striatum. In the hippocampus of hyperammonemic rats, only AMP deaminase activity was increased by 48% (p=0.0004), and in the cerebellum only ADA activity was increased significantly (by 26%, p<0.05). The adenylate pool size and energy charge were greatly reduced in the neocortex of hyperammonemic rats. Results suggested that two parallel pathways of AMP breakdown, including AMP deaminase and ADA, respectively, are up-regulated under pathological conditions, probably in order to overcome compensatory synthesis of adenylates, to ensure prompt adenylate pool depletion and reduce the adenylate energy charge in liver and selected brain regions.
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PMID:AMP deaminase and adenosine deaminase activities in liver and brain regions in acute ammonia intoxication and subacute toxic hepatitis. 1990 Apr 20


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