Electrochemical property of L-mandalate dehydrogenase

The direct electrochemistry of flavodehydrogenase domain (FDH) an genetically engineered enzyme, has been investigated at edge-plane pyrolytic graphite (EPG) electrode using poly-L-lysine as a promoter. Two redox couples (-0.481 V and -0.605 V vs SCE in the tris buffer solution at pH 7.5, scan rate 20 mV/s) were obtained on the cyclic voltammogram which respond to the separated two peaks in one-electron reduction-reoxidation steps of enzyme bounded flavin mononucleotide ( FMN). The electrochemical transformation of the substrate L-mandelic acid (LMA), catalysed by the FMN-fragment of L-mandalate dehydrogenase (LMDH) is inhibited at bare or promoter-modified EPG, but both ferrocenemonocarboxylic acid (FMCA) and cytochrome C, function as mediators.