B6-vitamer kinase involved in the salvage pathway of pyridoxal 5'-phosphate (PLP). Catalyzes the phosphorylation of pyridoxine (PN), pyridoxal (PL), and pyridoxamine (PM), forming their respective 5'-phosphorylated esters, i.e. PNP, PLP and PMP. ATP + pyridoxal = ADP + H(+) + pyridoxal 5'-phosphate ATP + pyridoxine = ADP + H(+) + pyridoxine 5'-phosphate ATP + pyridoxamine = ADP + H(+) + pyridoxamine 5'-phosphate Can use both zinc and magnesium that is complexed with ATP. However, magnesium seems to be the preferred metal used under physiological conditions. Is activated by the monovalent cation potassium. kcat is 140 min(-1) for the phosphorylation of PL with MgATP. kcat is 120 min(-1) for the phosphorylation of PL with ZnATP. kcat is 20 min(-1) for the phosphorylation of PN with MgATP. kcat is 40 min(-1) for the phosphorylation of PM with MgATP. kcat is 25 min(-1) for the phosphorylation of PM with ZnATP (at pH 7.3 and 37 degrees Celsius) (PubMed:15249053). kcat is 250 min(-1) for the phosphorylation of PL with MgATP (at pH 7.3 and 37 degrees Celsius) (PubMed:16740960). Cofactor metabolism; pyridoxal 5'-phosphate salvage; pyridoxal 5'-phosphate from pyridoxal: step 1/1. Cofactor metabolism; pyridoxal 5'-phosphate salvage; pyridoxine 5'-phosphate from pyridoxine: step 1/1. Cofactor metabolism; pyridoxal 5'-phosphate salvage; pyridoxamine 5'-phosphate from pyridoxamine: step 1/1. Homodimer. Cells lacking this gene lack pyridoxine kinase activity but still contain pyridoxal kinase activity (PubMed:8764513). Cells lacking this gene and cells lacking both pdxY and pdxK are not auxotrophs, meaning that the de novo pathway of PLP biosynthesis is functional. For PLP salvage, the pdxY single mutant can use both pyridoxine and pyridoxal, the pdxK single mutant can use pyridoxal but not pyridoxine, and the double mutant can no longer use both compounds (PubMed:9537380). Belongs to the pyridoxine kinase family. PdxK subfamily.