Catalyzes the phosphorylation of the dietary vitamin B6 vitamers pyridoxal (PL), pyridoxine (PN) and pyridoxamine (PM) to form pyridoxal 5'-phosphate (PLP), pyridoxine 5'-phosphate (PNP) and pyridoxamine 5'-phosphate (PMP), respectively (PubMed:9099727, PubMed:10987144, PubMed:17766369, PubMed:19351586, PubMed:31187503) (Probable). PLP is the active form of vitamin B6, and acts as a cofactor for over 140 different enzymatic reactions. ATP + pyridoxal = ADP + H(+) + pyridoxal 5'-phosphate ATP + pyridoxamine = ADP + H(+) + pyridoxamine 5'-phosphate ATP + pyridoxine = ADP + H(+) + pyridoxine 5'-phosphate Zn(2+) is the most effective divalent metal cation in vitro, followed by Co(2+), Mn(2+) and Mg(2+). Catalytic activity is inhibited competitively by 4-deoxypyridoxine, and is also inhibited by the benzodiazepine receptor ligands 1012S and ethyl-beta-carboline-3-carboxylate (PubMed:9099727). Inhibited by ginkgotoxin, theophylline, lamotrigine, enprofylline, theobromine, and caffeine (PubMed:22879864). Activity is increased in the presence of K(+)or Na(+) (PubMed:17766369). KM is <10 uM for pyridoxal (in the presence of K(+)) (PubMed:17766369). KM is <25 uM for MgATP (in the presence of K(+)) (PubMed:17766369). kcat is 200 min(-1) for phosphorylase activity using PL as substrate in the presence of Na(+). kcat is 85 min(-1) for phosphorylase activity using PL as substrate in the presence of K(+) (PubMed:17766369). kcat is 200 min(-1) for phosphorylase activity using PL as substrate in the presence of Na(+). kcat is 85 min(-1) for phosphorylase activity using PL as substrate in the presence of K(+) (PubMed:17766369). kcat is 29 min(-1) for phosphorylase activity using PL as substrate in the presence of Na(+) (PubMed:19351586). Optimum pH is 5.5-6.0. 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. Ubiquitous (PubMed:9099727, PubMed:31187503). Highly expressed in testis (PubMed:9099727). In adult testis and spermatozoa. Transcriptionally regulated by Sp1 transcription factor. The disease is caused by variants affecting the gene represented in this entry. Belongs to the pyridoxine kinase family.