MTSES is widely used in biochemical research, particularly in the study of protein structure and function. It is a water-soluble, membrane-impermeable thiol-specific reagent that modifies cysteine residues in proteins. This modification helps researchers investigate the role of specific cysteine residues in protein activity, folding, and interactions. MTSES is often employed in site-directed spin labeling (SDSL) experiments to study protein dynamics and conformational changes. Additionally, it is used in electrophysiology to modify ion channels and receptors, providing insights into their mechanisms and regulation. Its ability to introduce a negatively charged sulfonate group makes it valuable for probing electrostatic interactions within proteins.