Nivolumab anticancer monoclonal antibody native and denatured direct electrochemistry at a glassy carbon electrode

Abstract

Nivolumab (NIVO) is a recombinant humanized monoclonal antibody used in the immunotherapeutic treatment of cancer. The electrochemical oxidation of native NIVO, in solution and adsorbed on a glassy carbon electrode, using differential pulse voltammetry, showed two pH-dependent oxidation peaks, the first one corresponding to the cysteine amino acid residues, and the second one corresponding to the tyrosine and tryptophan amino acid residues. The interfacial behaviour and adsorption of native and denatured NIVO thick multilayer film adsorbed on glassy carbon electrode surface was probed by cyclic voltammetry and electrochemical impedance spectroscopy. The denaturation of a NIVO thick multilayer film adsorbed on a glassy carbon electrode surface, with chemical agents: denaturing agents urea and sodium dodecyl sulphate, and reductants tris(2-carboxyethyl)phosphine and dithiothreitol, was investigated electrochemically. The unfolded denatured adsorbed NIVO morphological structure, enhanced the exposure of more electroactive amino acid residues to the electrode surface, and a new additional peak, due to the tryptophan, methionine, and histidine amino acid residues oxidation, was found.