Thiol-specific spin label. Highly reactive thiol-specific spin label. Has been used to label cysteine residues in proteins (site-directed labeling, SDS-labeling). Allows protein structure and protein dynamics determination as well as the study of protein-protein and protein-oligonucleotide interactions. Alternative Name: (1-Oxyl-2,2,5,5-tetramethylpyrroline-3-methyl) methanethiosulfonate. Formula: C10H18NO3S2. MW: 264.3. CAS Number: 81213-52-7. Purity: ≥98% (HPLC). Appearance: Yellow crystalline solid. Solubility: Soluble in water, methanol, 100% ethanol, DMSO, acetonitrile or acetone. Long Term Storage: -20°C