Pyridoxine is a water-soluble vitamin. The body metabolizes this to pyridoxal phosphate, which the active cofactor. Pyridoxal phosphate (PLP) is involved in many different types of reactions involving amino acids. Reactions may involve the alpha, the beat, or the gamma carbon of the amino acid. Reactions at the alpha carbon include transamination reactions, aldol cleavages, de-aminations, decarboxylations, and racemizations. Reactions at the beta carbon include eliminations and replacements.
PLP commonly forms a Schiff base linkage to the amino acid substrate. The protonated ring system of PLP acts as an electron sink, to stabilize reaction intermediates carrying a negative charge.
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