title: F-ara-AMP is a substrate of cytoplasmic 5'-nucleotidase II (cN-II): HPLC and NMR studies of enzymatic dephosphorylation.
abstract: Intracellular accumulation of triphosphorylated derivatives is essential for the cytotoxic activity of nucleoside analogues. Different mechanisms opposing this accumulation have been described. We have investigated the dephosphorylation of monophosphorylated fludarabine (F-ara-AMP) by the purified cytoplasmic 5'-nucleotidase cN-II using HPLC and NMR. These studies clearly showed that cN-II was able to convert F-ara-AMP into its non phosphorylated form, F-ara-A, with a Km in the millimolar range and Vmax = 35 nmol/min/mg, with both methods. Cytoplasmic 5'-nucleotidase cN-II can degrade this clinically useful cytotoxic nucleoside analogue and its overexpression is thus likely to be involved in resistance to this compound.
authors.affiliation: INSERM U590, Laboratoire de Cytologie Analytique, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, Lyon, France. jordheim@yahoo.com
authors.forename: Lars P
authors.initials: LP
authors.lastname: Jordheim
authors.forename: Emeline
authors.initials: E
authors.lastname: Cros
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Galmarini
authors.forename: Charles
authors.initials: C
authors.lastname: Dumontet
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Bretonnet
authors.forename: Isabelle
authors.initials: I
authors.lastname: Krimm
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lancelin
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Gagnieu
mesh_terms: D015720:5'-Nucleotidase / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D003593:Cytoplasm / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D014740:Vidarabine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D001084:Vidarabine Phosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: D001084:Vidarabine Phosphate; C042382:fludarabine phosphate; D015720:5'-Nucleotidase; C508048:NT5C2 protein, human; D014740:Vidarabine; C024352:fludarabine