Higher order structure and free thiol

Abstract One of the major challenges in the biotherapeutics industry is maintaining the structural integrity and stability of the protein during the manufacture and shelf life. A well-developed panel of methods including “higher order structure (HOS)” methods is required to characterize and assess the consistency of the product quality. This chapter provides an overview of various techniques that are commonly applied in the HOS studies of therapeutic monoclonal antibodies (mAbs). Special emphasis is placed on the emerging nuclear magnetic resonance fingerprinting approach for HOS profiling as well as the current state-of-art technologies including Fourier transformation infrared spectroscopy, Raman, and fluorescence spectroscopy. Lastly, discussion on the determination of “free thiol” (or sulfhydryl group) which potentially affects protein tertiary structure is provided in this planned chapter.