= Pyridoxine phosphate
<Pyridoxine phosphate> is the 5′-phosphate derivative of <pyridoxine>, one of the forms of <Vitamin B6>. Attaching a <phosphate> group and changing an <alcohol> group into an <aldehyde> are different chemical modifications. <Pyridoxine phosphate> still differs from <pyridoxal phosphate>, the form used as a <coenzyme> in many reactions.<Vitamin B6 Fact Sheet for Health Professionals by the Office of Dietary Supplements>[Introduction: six vitamin B6 forms and their phosphorylated derivatives]{ref}
An important connection is the <oxidation> of <pyridoxine phosphate> by <pyridoxal 5'-phosphate synthase>. The official reaction is
$$
\mathrm{pyridoxine\ 5'\!\!\!-phosphate+O_2\longrightarrow pyridoxal\ 5'\!\!\!-phosphate+H_2O_2}.
$$
Here <oxygen> accepts the reducing equivalents, producing <hydrogen peroxide>; the <phosphate> group is retained. The <enzyme> contains <flavin mononucleotide>.<Pyridoxal 5'-phosphate synthase in IUBMB Enzyme Nomenclature>[EC 1.4.3.5, reaction (2) and Comments]{ref}
For a constructed material-balance example, complete conversion of 4 micromoles of <pyridoxine phosphate> through this reaction consumes 4 micromoles of <oxygen> and forms 4 micromoles each of <pyridoxal phosphate> and <hydrogen peroxide>. There is no net release of free <phosphate> in that reaction. Measuring only total phosphorus would therefore miss the conversion: the substrate and product each retain one phosphorus atom. A measurement that distinguishes their <functional groups> can answer a question that elemental accounting cannot.
Back to article page
