The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Peter Reichard - One of the best experts on this subject based on the ideXlab platform.
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effects of mutational loss of nucleoside kinases on Deoxyadenosine 5 phosphate Deoxyadenosine substrate cycle in cultured cem and v79 cells
Journal of Biological Chemistry, 1994Co-Authors: Vera Bianchi, Paola Ferraro, Stefania Borella, P Bonvini, Peter ReichardAbstract:Abstract The functions of a deoxynucleoside kinase and a deoxynucleotidase can give rise to substrate cycles in which the two enzymes catalyze in opposite directions the irreversible interconversion of a deoxynucleoside 5'-monophosphate (dNMP) and its deoxynucleoside. Earlier evidence showed that pyrimidine dNMP cycles occur in cultured cells and participate in the regulation of the size of dNMP pools there by affecting the transport of deoxyribonucleosides across the cell membrane. Here, we apply an isotope flow method using labeled adenine as precursor of dAMP and DNA to quantify Deoxyadenosine excretion as a measure of the catabolic activity of a putative dAMP/Deoxyadenosine cycle. A comparison of human CEM lymphoblasts and hamster V79 fibroblasts, including mutant cells lacking kinases for the phosphorylation of Deoxyadenosine, shows a much lower Deoxyadenosine excretion in CEM cells (0.05% of dATP synthesized by reduction of ADP) as compared with V79 cells (4% of dATP). Mutational loss of deoxycytidine kinase increases these values to 0.3% in CEM cells and to 10% in V79 cells. This strongly suggests the presence of a dAMP/Deoxyadenosine cycle in both CEM and V79 cells. Additional loss of adenosine kinase only marginally affects Deoxyadenosine excretion in CEM cells. The small excretion of Deoxyadenosine (also in the absence of both kinases) demonstrates that in CEM cells the in situ activity of the deoxynucleotidase affecting the dAMP/Deoxyadenosine substrate cycle is very low and that the cycle has mainly an anabolic function there.
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Effects of mutational loss of nucleoside kinases on Deoxyadenosine 5'-phosphate/Deoxyadenosine substrate cycle in cultured CEM and V79 cells.
Journal of Biological Chemistry, 1994Co-Authors: Vera Bianchi, Paola Ferraro, Stefania Borella, P Bonvini, Peter ReichardAbstract:Abstract The functions of a deoxynucleoside kinase and a deoxynucleotidase can give rise to substrate cycles in which the two enzymes catalyze in opposite directions the irreversible interconversion of a deoxynucleoside 5'-monophosphate (dNMP) and its deoxynucleoside. Earlier evidence showed that pyrimidine dNMP cycles occur in cultured cells and participate in the regulation of the size of dNMP pools there by affecting the transport of deoxyribonucleosides across the cell membrane. Here, we apply an isotope flow method using labeled adenine as precursor of dAMP and DNA to quantify Deoxyadenosine excretion as a measure of the catabolic activity of a putative dAMP/Deoxyadenosine cycle. A comparison of human CEM lymphoblasts and hamster V79 fibroblasts, including mutant cells lacking kinases for the phosphorylation of Deoxyadenosine, shows a much lower Deoxyadenosine excretion in CEM cells (0.05% of dATP synthesized by reduction of ADP) as compared with V79 cells (4% of dATP). Mutational loss of deoxycytidine kinase increases these values to 0.3% in CEM cells and to 10% in V79 cells. This strongly suggests the presence of a dAMP/Deoxyadenosine cycle in both CEM and V79 cells. Additional loss of adenosine kinase only marginally affects Deoxyadenosine excretion in CEM cells. The small excretion of Deoxyadenosine (also in the absence of both kinases) demonstrates that in CEM cells the in situ activity of the deoxynucleotidase affecting the dAMP/Deoxyadenosine substrate cycle is very low and that the cycle has mainly an anabolic function there.
Steven E J Bell - One of the best experts on this subject based on the ideXlab platform.
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surface enhanced raman evidence of protonation reorientation and ag complexation of Deoxyadenosine and Deoxyadenosine 5 monophosphate damp on ag and au surfaces
Journal of Physical Chemistry C, 2011Co-Authors: Evanthia Papadopoulou, Steven E J BellAbstract:Surface-enhanced Raman (SERS) spectra of Deoxyadenosine and 5′-dAMP on Ag and Au surfaces showed the protonation of both compounds in the N1 position, their orientation geometry on metal surfaces, and the formation of Ag+ complexes at alkaline pH on hydroxylamine-reduced Ag colloids. Interestingly, substitution at the N9 position caused dramatic changes in the relative band intensities within the spectra of both Deoxyadenosine and 5′-dAMP compared to that of simple adenine, although they continued to be dominated by adenine vibrations. Concentration-dependent spectra of 5′-dAMP were observed, which matched that of adenine at high concentrations and that of Deoxyadenosine at lower concentration (<10–4 M). This indicates that 5′-dAMP undergoes reorientation from flat to a more perpendicular orientation as the concentration increases. The result of these effects is that spectra of three different forms of Deoxyadenosine and five of 5′-dAMP can be observed, depending on the exact experimental conditions used....
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Surface-Enhanced Raman Evidence of Protonation, Reorientation, and Ag+ Complexation of Deoxyadenosine and Deoxyadenosine-5′-Monophosphate (dAMP) on Ag and Au Surfaces
Journal of Physical Chemistry C, 2011Co-Authors: Evanthia Papadopoulou, Steven E J BellAbstract:Surface-enhanced Raman (SERS) spectra of Deoxyadenosine and 5′-dAMP on Ag and Au surfaces showed the protonation of both compounds in the N1 position, their orientation geometry on metal surfaces, and the formation of Ag+ complexes at alkaline pH on hydroxylamine-reduced Ag colloids. Interestingly, substitution at the N9 position caused dramatic changes in the relative band intensities within the spectra of both Deoxyadenosine and 5′-dAMP compared to that of simple adenine, although they continued to be dominated by adenine vibrations. Concentration-dependent spectra of 5′-dAMP were observed, which matched that of adenine at high concentrations and that of Deoxyadenosine at lower concentration (
Vera Bianchi - One of the best experts on this subject based on the ideXlab platform.
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effects of mutational loss of nucleoside kinases on Deoxyadenosine 5 phosphate Deoxyadenosine substrate cycle in cultured cem and v79 cells
Journal of Biological Chemistry, 1994Co-Authors: Vera Bianchi, Paola Ferraro, Stefania Borella, P Bonvini, Peter ReichardAbstract:Abstract The functions of a deoxynucleoside kinase and a deoxynucleotidase can give rise to substrate cycles in which the two enzymes catalyze in opposite directions the irreversible interconversion of a deoxynucleoside 5'-monophosphate (dNMP) and its deoxynucleoside. Earlier evidence showed that pyrimidine dNMP cycles occur in cultured cells and participate in the regulation of the size of dNMP pools there by affecting the transport of deoxyribonucleosides across the cell membrane. Here, we apply an isotope flow method using labeled adenine as precursor of dAMP and DNA to quantify Deoxyadenosine excretion as a measure of the catabolic activity of a putative dAMP/Deoxyadenosine cycle. A comparison of human CEM lymphoblasts and hamster V79 fibroblasts, including mutant cells lacking kinases for the phosphorylation of Deoxyadenosine, shows a much lower Deoxyadenosine excretion in CEM cells (0.05% of dATP synthesized by reduction of ADP) as compared with V79 cells (4% of dATP). Mutational loss of deoxycytidine kinase increases these values to 0.3% in CEM cells and to 10% in V79 cells. This strongly suggests the presence of a dAMP/Deoxyadenosine cycle in both CEM and V79 cells. Additional loss of adenosine kinase only marginally affects Deoxyadenosine excretion in CEM cells. The small excretion of Deoxyadenosine (also in the absence of both kinases) demonstrates that in CEM cells the in situ activity of the deoxynucleotidase affecting the dAMP/Deoxyadenosine substrate cycle is very low and that the cycle has mainly an anabolic function there.
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Effects of mutational loss of nucleoside kinases on Deoxyadenosine 5'-phosphate/Deoxyadenosine substrate cycle in cultured CEM and V79 cells.
Journal of Biological Chemistry, 1994Co-Authors: Vera Bianchi, Paola Ferraro, Stefania Borella, P Bonvini, Peter ReichardAbstract:Abstract The functions of a deoxynucleoside kinase and a deoxynucleotidase can give rise to substrate cycles in which the two enzymes catalyze in opposite directions the irreversible interconversion of a deoxynucleoside 5'-monophosphate (dNMP) and its deoxynucleoside. Earlier evidence showed that pyrimidine dNMP cycles occur in cultured cells and participate in the regulation of the size of dNMP pools there by affecting the transport of deoxyribonucleosides across the cell membrane. Here, we apply an isotope flow method using labeled adenine as precursor of dAMP and DNA to quantify Deoxyadenosine excretion as a measure of the catabolic activity of a putative dAMP/Deoxyadenosine cycle. A comparison of human CEM lymphoblasts and hamster V79 fibroblasts, including mutant cells lacking kinases for the phosphorylation of Deoxyadenosine, shows a much lower Deoxyadenosine excretion in CEM cells (0.05% of dATP synthesized by reduction of ADP) as compared with V79 cells (4% of dATP). Mutational loss of deoxycytidine kinase increases these values to 0.3% in CEM cells and to 10% in V79 cells. This strongly suggests the presence of a dAMP/Deoxyadenosine cycle in both CEM and V79 cells. Additional loss of adenosine kinase only marginally affects Deoxyadenosine excretion in CEM cells. The small excretion of Deoxyadenosine (also in the absence of both kinases) demonstrates that in CEM cells the in situ activity of the deoxynucleotidase affecting the dAMP/Deoxyadenosine substrate cycle is very low and that the cycle has mainly an anabolic function there.
B H Berg - One of the best experts on this subject based on the ideXlab platform.
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reversal of the effect of 17 beta estradiol 17 beta acetate on aminoacyl trna synthetase phosphatase and aminoacyl trna synthetase activities in the uterus and liver of ovariectomized bom nmri mice by 2 Deoxyadenosine 3 phosphate
Iubmb Life, 1993Co-Authors: B H BergAbstract:: When an adenylyl cyclase inhibitor, 2-Deoxyadenosine 3'-phosphate, was administered together with 17-beta-estradiol 17-beta-acetate on ovariectomized Bom:NMRI mice, the short term effects of the hormone on the uterus aminoacyl-tRNA synthetase phosphatase and aminoacyl-tRNA synthetase activities were reversed, whereas the effect on the liver enzymes was about the same for 17-beta-estradiol 17-beta-acetate and for 2-Deoxyadenosine 3-phosphate.
Evanthia Papadopoulou - One of the best experts on this subject based on the ideXlab platform.
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surface enhanced raman evidence of protonation reorientation and ag complexation of Deoxyadenosine and Deoxyadenosine 5 monophosphate damp on ag and au surfaces
Journal of Physical Chemistry C, 2011Co-Authors: Evanthia Papadopoulou, Steven E J BellAbstract:Surface-enhanced Raman (SERS) spectra of Deoxyadenosine and 5′-dAMP on Ag and Au surfaces showed the protonation of both compounds in the N1 position, their orientation geometry on metal surfaces, and the formation of Ag+ complexes at alkaline pH on hydroxylamine-reduced Ag colloids. Interestingly, substitution at the N9 position caused dramatic changes in the relative band intensities within the spectra of both Deoxyadenosine and 5′-dAMP compared to that of simple adenine, although they continued to be dominated by adenine vibrations. Concentration-dependent spectra of 5′-dAMP were observed, which matched that of adenine at high concentrations and that of Deoxyadenosine at lower concentration (<10–4 M). This indicates that 5′-dAMP undergoes reorientation from flat to a more perpendicular orientation as the concentration increases. The result of these effects is that spectra of three different forms of Deoxyadenosine and five of 5′-dAMP can be observed, depending on the exact experimental conditions used....
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Surface-Enhanced Raman Evidence of Protonation, Reorientation, and Ag+ Complexation of Deoxyadenosine and Deoxyadenosine-5′-Monophosphate (dAMP) on Ag and Au Surfaces
Journal of Physical Chemistry C, 2011Co-Authors: Evanthia Papadopoulou, Steven E J BellAbstract:Surface-enhanced Raman (SERS) spectra of Deoxyadenosine and 5′-dAMP on Ag and Au surfaces showed the protonation of both compounds in the N1 position, their orientation geometry on metal surfaces, and the formation of Ag+ complexes at alkaline pH on hydroxylamine-reduced Ag colloids. Interestingly, substitution at the N9 position caused dramatic changes in the relative band intensities within the spectra of both Deoxyadenosine and 5′-dAMP compared to that of simple adenine, although they continued to be dominated by adenine vibrations. Concentration-dependent spectra of 5′-dAMP were observed, which matched that of adenine at high concentrations and that of Deoxyadenosine at lower concentration (