Effects of Al(III) and Nano- ${\rm Al}_{13}$ on Aldehyde Dehydrogenase Activity on Reduced Graphene Oxide Modified Electrode

In this paper, electrochemical tests are applied to investigate the effects of Al(III) and nano-sized tridecameric aluminum polycation (nano- Al₁₃) on aldehyde dehydrogenase (ALDH) activity, by using reduced graphene oxide chemically modified electrodes. The amperometric i-t curves for the oxidation of the enzymatically generated diphosphopyridine nucleotide-reduced disodium salt (NADH) are collected, and the ALDH activity is determined indirectly, depending on the changes of the oxidation current of NADH. The results show that Al(III) and nano-Al₁₃ exhibit effective inhibition on ALDH activity. The proposed mechanism of the effects is explored by means of various analytical techniques, such as fluorescence spectroscopy and circular dichroism. Based on the characterization methods mentioned above, the remarkable activity reduction of ALDH might be ascribed to the conformational changes of coenzyme nicotinamide adenine dinucleotide (NAD⁺) induced by different aluminum species.