title: Apparent pyridoxine transport mutants of Escherichia coli with pyridoxal kinase deficiency.
abstract: By nitrosoguanidine treatment of a vitamin B-6 auxotroph (KG980) of Escherichia coli, mutants were isolated that require for growth markedly higher concentrations of pyridoxine than the parent strain. One of the mutants, strain HN1, exhibited a severely reduced ability to take up extracellular pyridoxine. Besides, cell-free extracts of HN1 showed an extremely low activity to phosphorylate pyridoxine compared to that of KG980. These findings together with other results suggest that phosphorylation of pyridoxine is essential for the concentration uptake of the vitamin.
mesh_terms: D001692:Biological Transport; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D009154:Mutation; D009604:Nitrosoguanidines / Q000494:pharmacology; D010770:Phosphotransferases / Q000378:metabolism*; D011731:Pyridoxal Kinase / Q000378:metabolism*; D011734:Pyridoxaminephosphate Oxidase / Q000378:metabolism; D011736:Pyridoxine / Q000378:metabolism*
chemical_list: D009604:Nitrosoguanidines; D011734:Pyridoxaminephosphate Oxidase; D010770:Phosphotransferases; D011731:Pyridoxal Kinase; D011736:Pyridoxine