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Dinucleoside tetraphosphatase from human blood cells. Purification and characterization as a high specific activity
R M Pinto1, M J Costas, A Fernández
1Departamento de Bioquimica y Biología Molecular y Genética, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain.
Abstract:
Dinucleoside tetraphosphatase (Np4Nase; EC 3.6.1.17) has been purified 170,000-fold from a 30-60% ammonium sulfate fraction of a human blood cell extract. Purification included a dye-ligand affinity elution step using the inhibitor adenosine 5'-tetraphosphate. Human blood Np4Nase resembled rat liver Np4Nase, including recognition by anti-rat Np4Nase, but differed from homogeneous human leukemia Np4Nase in the 1000-fold lower specific activity of the latter. The results are discussed in relation to the potential role of diadenosine tetraphosphate (Ap4A) in the control of cell division and the turnover of Ap4A in blood.