Characterization of ectonucleotidases on vascular smooth-muscle cells
- 1 September 1985
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 230 (2), 503-507
- https://doi.org/10.1042/bj2300503
Abstract
We compared the properties of the ectonucleotidases (nucleoside triphosphatase, EC 3.6.1.15; nucleoside diphosphatase, EC 3.6.1.6; 5′-nucleotidase, EC 3.1.3.5) in intact pig aortic smooth-muscle cells in culture with the properties that we previously investigated for ectonucleotidases of aortic endothelial cells [Cusack, Pearson & Gordon (1983) Biochem. J. 214, 975-981]. In experiments with nucleotide phosphorothioate diastereoisomers, stereoselective catabolism of adenosine 5′-[β-thio]triphosphate, but not of adenosine 5′-[α-thio]triphosphate, by the triphosphatase and stereoselective catabolism of adenosine 5′-[α-thio]diphosphate by the diphosphatase were found, as occurs in endothelial cells. In contrast with endothelial ecto-5′-nucleotidase, the smooth-muscle-cell enzyme catabolized adenosine 5′-monophosphorothioate (AMPS) to adenosine: the affinity of the enzyme for AMPS was greater than for AMP, and Vmax for AMPS was about one-sixth that for AMP. In both cell types AMPS was an apparently competitive inhibitor of AMP catabolism by 5′-nucleotidase. The relative rates of catabolism of nucleotide enantiomers in which the natural D-ribofuranosyl moiety is replaced by an L-ribofuranosyl moiety were similar to those in endothelial cells. No ectopyrophosphatase activity was detected in smooth-muscle cells, in contrast with endothelial cells, where modest activity is present.This publication has 18 references indexed in Scilit:
- The role of adenosine in the regulation of coronary blood flow.Circulation Research, 1980
- Metabolism of adenine nucleotides by ectoenzymes of vascular endothelial and smooth-muscle cells in cultureBiochemical Journal, 1980
- Enzyme activities in endothelial cells and smooth muscle cells from swine aorta.Proceedings of the National Academy of Sciences, 1979
- Uptake and metabolism of adenosine by pig aortic endothelial and smooth-muscle cells in cultureBiochemical Journal, 1978
- Investigation of Enzyme Mechanisms with Nucleoside PhosphorothioatesAngewandte Chemie International Edition in English, 1975
- The direct linear plot. A new graphical procedure for estimating enzyme kinetic parametersBiochemical Journal, 1974
- Purinergic nerves.1972
- Metabolism of [14C]adenine and derivatives by cerebral tissues, superfused and electrically stimulatedBiochemical Journal, 1972
- NucleosideBiochimica et Biophysica Acta (BBA) - Enzymology, 1967
- PLAQUE FORMATION AND ISOLATION OF PURE LINES WITH POLIOMYELITIS VIRUSESThe Journal of Experimental Medicine, 1954