Stimulation by glycerate 2,3-bisphosphate: a common property of cytosolic IMP-GMP 5'-nucleotidase in rat and human tissues |
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| Authors: | F Bontemps M F Vincent F Van den Bergh G van Waeg G Van den Berghe |
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| Affiliation: | Laboratory of Physiological Chemistry, University of Louvain, Brussels, Belgium. |
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| Abstract: | Glycerate 2,3-bisphosphate, a potent stimulator of the cytosolic 5'-nucleotidase which preferentially hydrolyzes IMP and GMP in human erythrocytes (Bontemps et al., 1988, Biochem. J. 250, 687-696), also stimulates the dephosphorylation of IMP in cytosol fractions of rat heart, liver, brain, kidney, spleen and erythrocytes, and of human polymorphonuclear leucocytes, mixed peripheral blood lymphocytes, platelets and fibroblasts. Depending on the cell type, stimulation by 5 mM glycerate 2,3-bisphosphate varied from 1.5- to 12-fold. Where investigated, glycerate 2,3-bisphosphate had an approx. 5-fold higher affinity for the enzyme than its other stimulator, ATP. These observations provide a useful tool to distinguish IMP-GMP 5'-nucleotidase from other 5'-nucleotidases, and suggest a common origin of the cytosolic IMP-GMP 5'-nucleotidase in various tissues. |
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