Hydration-dehydration of the electroactive group on the electrochemical behaviour of pyridoxal-5′-phosphate

Abstract A study on the electrochemical behaviour of pyridoxal-5′-phosphate (PLP) at a d.m.e. over a wide pH range was carried out. Attention was mainly focused on the hydration-dehydration reaction of the carbonyl group of PLP. The polarographic and voltammetric results show that the reduction process is kinetically controlled, although to a different extent, depending on the pH. The influence of homogeneous protonation equilibria was analyzed, and rate and equilibrium constant data for the chemical reaction were evaluated.