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1 Final Report on the Safety Assessment of Polysorbates 20, 21, 40, 60, 61, 65, 80, 81, and 85. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818409021272] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Polysorbates are a series of polyoxyethylenated sorbitan esters that are used as hydrophilic, nonionic surfactants in a variety of cosmetic products. Polysorbates are hydrolyzed by pancreatic and blood lipases; the fatty acid moiety is released to be absorbed and metabolized, whereas the polyoxyethylene sorbitan moiety is very poorly absorbed and is excreted unchanged. Acute and long-term oral toxicity in animals indicates a low order of toxicity with oral ingestion of the Polysorbates. Polysorbate 80 was shown to be nonmutagenic in the Ames and micronucleus tests. The Polysorbates were noncarcinogenic in laboratory animals. Multiple studies have shown that the Polysorbates enhance the activity of known chemical carcinogens while not actually being carcinogenic themselves. Extensive clinical skin testing showed Polysorbates to have little potential for human skin irritation or evidence of skin sensitization or phototoxicity. The available data indicate that these ingredients are used in numerous preparations without clinical reports of significant adverse effects. It is concluded that they are safe for use in cosmetics at present concentrations of use.
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Martini D, Ranieri-Raggi M, Sabbatini ARM, Moir AJG, Polizzi E, Mangani S, Raggi A. Characterization of the metallocenter of rabbit skeletal muscle AMP deaminase. A new model for substrate interactions at a dinuclear cocatalytic Zn site. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1508-18. [PMID: 17991449 DOI: 10.1016/j.bbapap.2007.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2007] [Revised: 09/19/2007] [Accepted: 10/03/2007] [Indexed: 11/28/2022]
Abstract
We have previously provided evidence for a dinuclear zinc site in rabbit skeletal muscle AMPD compatible with a (micro-aqua)(micro-carboxylato)dizinc(II) core with an average of two histidine residues at each metal site. XAS of the zinc binding site of the enzyme in the presence of PRN favors a model where PRN is added to the coordination sphere of one of the two zinc ions increasing its coordination number to five. The uncompetitive nature of the inhibition of AMPD by fluoride reveals that the anion probably displaces the nucleophile water molecule terminally coordinated to the catalytic Zn(1) ion at the enzyme C-terminus, following the binding of AMP at the Zn(2) ion located at N-terminus of the enzyme. Thus, the two Zn ions in the AMPD metallocenter operate together as a single catalytic unit, but have independent function, one of them (Zn(1)) acting to polarize the nucleophile water molecule, whilst the other (Zn(2)) acts transiently as a receptor for an activating substrate molecule. The addition of fluoride to AMPD also abolishes the cooperative behaviour induced in the enzyme by the inhibitory effect of ATP at acidic pH that probably resides in the competition with the substrate for an adenine nucleotide specific regulatory site located in the Zn(2) ion binding region and which is responsible for the positive homotropic cooperativity behaviour of AMPD.
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Affiliation(s)
- Daniela Martini
- Dipartimento di Scienze dell'Uomo e dell'Ambiente, Chimica e Biochimica Medica, Università di Pisa, Via Roma 55, 56126 Pisa, Italy
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Torrecilla A, Marques AF, Buscalioni RD, Oliveira JM, Teixeira NA, Atencia EA, Günther Sillero MA, Sillero A. Metabolic fate of AMP, IMP, GMP and XMP in the cytosol of rat brain: an experimental and theoretical analysis. J Neurochem 2001; 76:1291-307. [PMID: 11238714 DOI: 10.1046/j.1471-4159.2001.00084.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A systematic study of the metabolic fate of AMP, IMP, GMP and XMP (NMP) in the presence of cytosol from rat brain is here presented; the kinetics of both disappearance of NMP, and appearance of their degradation products was followed by HPLC. In the absence of ATP, AMP was preferentially degraded to adenosine with concomitant appearance of inosine and hypoxanthine. In the presence of ATP, AMP was preferentially degraded via IMP. The nucleosides generated in the course of the reactions are further degraded, almost exclusively, via nucleoside phosphorylase using as cofactor the P(i) generated in the reaction mixture. In order to quantify the effect of each one of the enzymes involved in the degradation of NMP, two complementary approaches were followed: (i) the V:(max) and K:(m) values of the enzymes acting in the intermediate steps of the reactions were determined; (ii) these data were introduced into differential equations describing the concentration of the nucleotides and their degradation products as a function of the time of incubation. Factors affecting kinetic parameters of the equation velocity as a function of ATP concentration were introduced when required. The differential equations were solved with the help of Mathematica 3.0. The theoretical method can be used to simulate situations not feasible to be carried out, such as to measure the influence of nM-microM concentrations of ATP on the metabolism of AMP.
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Affiliation(s)
- A Torrecilla
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas Alberto Sols (UAM/CSIC), Facultad de Medicina, Madrid, Spain
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Van den Berghe G, Bontemps F, Vincent MF, Van den Bergh F. The purine nucleotide cycle and its molecular defects. Prog Neurobiol 1992; 39:547-61. [PMID: 1529104 DOI: 10.1016/0301-0082(92)90006-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Three enzymes of purine metabolism, adenylosuccinate synthetase, adenylosuccinate lyase and AMP deaminase, have been proposed to form a functional unit, termed the purine nucleotide cycle. This cycle converts AMP into IMP and reconverts IMP into AMP via adenylosuccinate, thereby producing NH3 and forming fumarate from aspartate. In muscle, the purine nucleotide cycle has been shown to function during intense exercise; the metabolic flux through the cycle has been proposed to play a role in the regeneration of ATP by pulling the adenylate kinase reaction in the direction of formation of ATP, and by providing Krebs cycle intermediates. In kidney, the purine nucleotide cycle was shown to account for the release of NH3 under the normal acid-base status, but not under acidotic conditions. In brain, the purine nucleotide cycle might function under conditions that induce a loss of ATP, and thereby contribute to its recovery. There is no evidence that the purine nucleotide cycle operates in liver. Deficiency of muscle AMP deaminase is an apparently frequent disorder, which might affect approximately 2% of the general population. The observation that it can be found in clinically asymptomatic individuals suggests, paradoxically, that the ATP-regenerating function which has been attributed to the purine nucleotide cycle is not essential for muscle function. Further work should be aimed at identifying the conditions under which AMP deaminase deficiency becomes symptomatic. Adenylosuccinate lyase deficiency provokes psychomotor retardation, often accompanied by autistic features. Its clinical heterogeneity justifies systematic screening in patients with unexplained mental deficiency. Additional studies are required to determine the mechanisms whereby this enzyme defect results in psychomotor retardation.
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Affiliation(s)
- G Van den Berghe
- Laboratory of Physiological Chemistry, International Institute of Cellular and Molecular Pathology, Brussels, Belgium
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Malliaros DP, Kozwich DL, Jahngen EG. Purification and characterization of developmentally regulated AMP deaminase from Dictyostelium discoideum. Differentiation 1991; 46:153-60. [PMID: 1916064 DOI: 10.1111/j.1432-0436.1991.tb00876.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AMP deaminase, the enzyme that catalyzes the conversion of adenosine monophosphate (AMP) to inosine monophosphate (IMP) and ammonia, was purified from the cellular slime mold, Dictyostelium discoideum in the nutrient-deprived state. The native enzyme had an apparent molecular weight of 199,000 daltons. Its apparent Km was 1.6 mM and its Vmax was 1.0 mumol min-1 mg-1, as measured by the release of IMP From AMP. The enzyme, like other AMP deaminases, was found to be activated by ATP, and inhibited either by GTP or inorganic phosphate. It was also specific for the deamination of AMP. Deaminase activity was increased either when vegetative cells were placed in a nutrient-deprived medium (for up to 6 h) or when vegetative cells were treated with the drug hadacidin. In cells actively growing in complete media, enzyme activity was more non-specific, hydrolyzing adenosine as well as AMP. AMP deaminase in D. discoideum appears to be stage-specific and developmentally regulated, possibly serving to regulate the adenylated nucleotide pool and the interconversion to guanylated nucleotides during early morphodifferentiation.
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Affiliation(s)
- D P Malliaros
- Department of Chemistry, University of Lowell, MA 01854
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6
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Adenylate deaminase deficiency in a mutant murine T cell lymphoma cell line. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38421-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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7
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Hanson S, Ullman B. AMP deaminase and thymidine kinase deficiencies in a mutant mouse S49 cell clone. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1989; 253B:79-86. [PMID: 2610148 DOI: 10.1007/978-1-4684-5676-9_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
From a mutagenized population of wild type S49 cells, a clone was isolated in a single step that possessed functional and biochemical deficiencies in both AMP deaminase and thymidine kinase activities. This mutant cell line, DTB6, was selected in semi-solid medium containing 1mM thymidine and 1mM dibutyryl cyclic AMP. In comparative growth rate experiments, DTB6 cells were considerably less sensitive than parental cells to the growth inhibitory effects of thymidine. In contrast, DTB6 cells were much more sensitive to the cytotoxic effects of adenine and adenosine. The supersensitivity of DTB6 cells toward adenine could be ameliorated by the addition of hypoxanthine to the culture medium. The growth phenotype of the mutant cells could be attributed to deficiencies in two enzyme activities. First, DTB6 cells possessed a 60-70% deficiency in AMP deaminase activity, although the residual activity appeared kinetically similar to the wild type enzyme. Second, DTB6 cells possessed a virtual complete deficiency in thymidine kinase activity. Both enzyme deficiencies behaved in a recessive fashion in intraspecies hybrids. Revertants of DTB6 cells possessed wild type levels of AMP deaminase activity but remained deficient in thymidine kinase activity, while another revertant of DTB6 cells expressed 11% of the wild type thymidine kinase level but did not perceptibly change its AMP deaminase activity. The ability to isolate single step mutants with two seemingly independent biochemical abnormalities raises the speculation that there may be some link between cellular functions responsible for purine nucleotide and thymidine metabolism.
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Affiliation(s)
- S Hanson
- Department of Biochemistry, Oregon Health Sciences University, Portland 97201
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8
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Barshop BA, Frieden C. Analysis of the interaction of rabbit skeletal muscle adenylate deaminase with myosin subfragments. A kinetically regulated system. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43621-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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10
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Raffin JP. AMP deaminase from the gill of Salmo gairdnerii Richardson: effects of anions, cations and buffers. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1984; 79:499-504. [PMID: 6509939 DOI: 10.1016/0305-0491(84)90412-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The AMP deaminase isoenzymes from trout gill were activated by sodium and potassium, sodium being the most efficient. The optimal concentration for activation was 30-50 mM. The enzyme was sensitive to ionic strength, and imidazole was an inhibitor at concentrations higher than 25 mM. A possible regulation of gill AMP deaminase by intracellular imidazole buffers is discussed. AMP deaminase activity was tested in the presence of physiological concentrations of sodium and potassium. When the concentration of one of these cations was varied around its physiological concentration, the enzyme activity was relatively stable, indicating that the intracellular AMP deaminase activity would be insensitive to changes in the concentrations of monovalent cations. The effects of the sodium salts of different inorganic and organic anions were tested. Except chloride and gluconate, all were inhibitors of gill AMP deaminase.
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11
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Mills GC, Goldblum RM, Schmalstieg FC. Catabolism of adenine nucleotides in adenosine deaminase deficient erythrocytes. Life Sci 1981; 29:1811-20. [PMID: 7300574 DOI: 10.1016/0024-3205(81)90193-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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12
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Buchwald M, Ullman B, Martin D. Biochemical and genetic analysis of AMP deaminase deficiency in cultured mammalian cells. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68625-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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13
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Stelmach H, Jaroszewicz L. Pig thyroid AMP deaminase purification and some properties. Biochem Biophys Res Commun 1981; 101:144-52. [PMID: 7283996 DOI: 10.1016/s0006-291x(81)80022-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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14
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Regulatory properties of AMP-deaminase from lateral red muscle and dorsal white muscle of goldfish, Carassius auratus (L.). ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0305-0491(81)90331-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Raffin J, Leray C. Comparative study on AMP deaminase in gill, muscle and blood of fish. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0305-0491(80)90411-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Shiraki H, Ogawa H, Matsuda Y, Nakagawa H. Interaction of rat muscle AMP deaminase with myosin. II. Modification of the kinetic and regulatory properties of rat muscle AMP deaminase by myosin. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 566:345-52. [PMID: 420860 DOI: 10.1016/0005-2744(79)90038-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The problems of whether the kinetic and regulatory properties of AMP deaminase were modified by formation of a deaminase-myosin complex were investigated with an enzyme preparation from rat skeletal muscle. Results showed that AMP deaminase was activated by binding to myosin. Myosin-bound AMP deaminase showed a sigmoidal activity curve with respect to AMP concentration in the absence of ATP and ADP, but a hyperbolic curve in their presence. Addition of ATP and ADP doubled the V value, but did not affect the Km value. Myosin-bound AMP deaminase also gave a sigmoidal curve in the presence of alkali metal ions, whereas free AMP deaminase gave a hyperbolic curve. GTP abolished the activating effects of both myosin and ATP.
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17
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Raffin JP, Leray C. AMP deaminase in the gill of trout (Salmo gairdneri R.). Modalities of an activation by cellular proteolytic enzymes. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1979; 62:23-9. [PMID: 95690 DOI: 10.1016/0305-0491(79)90006-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. The AMP deaminase activity present in a crude extract of trout gill increased with time. 2. Soybean trypsin inhibitor and alpha2-macroglobulin inhibited the AMP deaminase activation. NEM was also inhibitory at 10-3 M. 3. The activation process is followed by a decrease of activity which is inhibited by EGTA and enhanced by Mg2+. These two compounds were without effect on the activation process itself. 4. Trypsin induces a sharp activation of AMP deaminase in a fresh gill extract but is without effect on a fully activated extract. 5. Overall, the results suggest that neutral proteinases are implicated in AMP deaminase activation.
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Affiliation(s)
- J P Raffin
- Laboratoire de Physiologie comparée des Regulations, C.N.R.S., - B.P.CR, 67037 Strasbourg-Cédex, France
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18
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Leray C, Raffin JP, Winninger C. Aspects of purine metabolism in the gill epithelium of rainbow trout, Salmo gairdneri Richardson. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1979; 62:31-40. [PMID: 318437 DOI: 10.1016/0305-0491(79)90007-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
1. Enzymes interconnecting the adenylate pool were present in high concentration. 2. AMP and adenosine were easily deaminated by the corresponding enzymes whose high levels were detected. 3. Adenylate was hydrolyzed either by deamination to yield IMP which was further dephosphorylated to inosine or by dephosphorylation to adenosine followed by deamination to inosine. 4. Incubation of gill extract with [-14C]-AMP in the presence and absence of ATP but with adenosine deaminase inhibitors allowed demonstration that ATP controlled the balance between these pathways. 5. Some biochemical properties of 5'-nucleotidase. AMP deaminase and adenosine deaminase were defined. 6. Purine salvage enzymes were also estimated.
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Affiliation(s)
- C Leray
- Laboratoire de Physiologie comparée des Régulations, C.N.R.S., B.P. 20 C.R., 67037 Strasbourg-Cédex, France
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19
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Leung HB, Schramm VL. The role of adenosine monophosphate nucleosidase in the regulation of adenine nucleotide levels in Azotobacter vinelandii during aerobic-anaerobic transitions. Arch Biochem Biophys 1978; 190:46-56. [PMID: 708078 DOI: 10.1016/0003-9861(78)90252-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Makarewicz W, Stankiewicz A. AMP-aminohydrolase of human skeletal muscle: partial purification and properties. BIOCHEMICAL MEDICINE 1974; 10:180-97. [PMID: 4208518 DOI: 10.1016/0006-2944(74)90021-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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23
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Von Schwarz Z. Zur Regulation der NADP-abhängigen Glycerinaldehyd-3-phosphat-Dehydrogenase in den Primärblättern von Phaseolus vulgaris L. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/s0015-3796(17)30088-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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24
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Chapman AG, Atkinson DE. Stabilization of Adenylate Energy Charge by the Adenylate Deaminase Reaction. J Biol Chem 1973. [DOI: 10.1016/s0021-9258(19)43229-8] [Citation(s) in RCA: 171] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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25
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MacDonnell PC, Tillinghast EK. Metabolic sources of ammonia in the earthworm,Lumbricus terrestris L. ACTA ACUST UNITED AC 1973. [DOI: 10.1002/jez.1401850202] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bishop SH, Barnes LB. Ammonia forming mechanisms: deamination of 5'-adenylic acid (AMP) by some polychaete annelids. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1971; 40:407-22. [PMID: 5120306 DOI: 10.1016/0305-0491(71)90225-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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3 Purine, Purine Nucleoside, and Purine Nucleotide Aminohydrolases. ACTA ACUST UNITED AC 1971. [DOI: 10.1016/s1874-6047(08)60363-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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30
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Kizer DE, Howell BA. Stimulation of DNA synthesis and AMP deaminase activity in rat hearts during isoproterenol-induced myocardial infarction. Chem Biol Interact 1970; 2:235-46. [PMID: 5524164 DOI: 10.1016/0009-2797(70)90026-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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31
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Kizer DE, Smith LD, Howell BA. Kinetic and immunochemical evidence for induction of hepatic adenosine monophosphate deaminase by 3′-methyl-4-dimethylaminoazobenzene or thioacetamide. Biochem Pharmacol 1970. [DOI: 10.1016/0006-2952(70)90041-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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32
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Effect of Salts on Inhibition of Chicken Muscle Adenosine Monophosphate Deaminase by Phosphate Esters and Inorganic Phosphate. J Biol Chem 1970. [DOI: 10.1016/s0021-9258(18)63213-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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33
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Murray AW, Elliott DC, Atkinson MR. Nucleotide biosynthesis from preformed purines in mammalian cells: regulatory mechanisms and biological significance. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1970; 10:87-119. [PMID: 4910307 DOI: 10.1016/s0079-6603(08)60562-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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34
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Smith LD, Kizer DE. Purification and properties of rat liver AMP deaminase. BIOCHIMICA ET BIOPHYSICA ACTA 1969; 191:415-24. [PMID: 4982146 DOI: 10.1016/0005-2744(69)90260-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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35
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Raivio KO, Kekomäki MP, Mäenpää PH. Depletion of liver adenine nucleotides induced by D-fructose. Dose-dependence and specificity of the fructose effect. Biochem Pharmacol 1969; 18:2615-24. [PMID: 5403997 DOI: 10.1016/0006-2952(69)90192-0] [Citation(s) in RCA: 140] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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36
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Rubio R, Berne RM. Release of adenosine by the normal myocardium in dogs and its relationship to the regulation of coronary resistance. Circ Res 1969; 25:407-15. [PMID: 5347222 DOI: 10.1161/01.res.25.4.407] [Citation(s) in RCA: 225] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The evidence supporting the hypothesis that adenosine is the mediator of metabolic regulation of coronary blood flow was obtained from experiments characterized by myocardial hypoxia. If adenosine serves the role of physiological regulator of coronary blood flow, it must also be released by the normal heart. Experiments designed to study this question were performed on 15 open-chest dogs in which adenosine was sought in perfusates of the epicardial surface of the well-oxygenated heart. The pericardial space was perfused with warm (37°C) Tyrode's or Krebs-Henseleit solutions (400 to 1200 ml over 1 to 3 hours), and the perfusates were analyzed for adenosine. With a normal myocardial oxygen supply, adenosine was present in the perfusates in a concentration of 3.1 ± 0.5 x 10>
-8
M. Partial asphyxia, induced by reducing pulmonary ventilation, significantly (
P
≤ 0.02) increased the adenosine concentration of the perfusates to 5.4 ± 0.8 x 10
-8
M. In four dogs the normal pericardial fluid was found to contain adenosine in a concentration of 10.9 ± 2.9 x 10
-7
M, which probably represents the basal extracellular adenosine concentration in the myocardium. The results indicate that the normal myocardial cells release adenosine continuously into the surrounding interstitial fluid, and it is suggested that the level of the interstitial fluid concentration of adenosine probably regulates coronary blood flow to maintain the oxygen balance of the myocardium.
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