4-Hydroxy- L -threonine, a committed precursor of pyridoxol (vitamin B 6 )

Having established in an earlier experiment that, in Escherichia coli, 4-hydroxy-L-threonine [(2S,3S)-2-amino-3,4-dihydroxybutanoic acid] lies on the route from glucose to vitamin B6, it is now demonstrated that the amino acid serves as a precursor of pyridoxol, since 13C NMR spectroscopy shows that the intact C-2,3 bond of [2,3-13C2]-4-hydroxy-L-threonine 2 becomes the C-5,6 bond of pyridoxol 1.