Intra-molecular reactions as a new approach to investigate bio-radical reactivity: a case study of cysteine sulfinyl radicals.

Herein, we demonstrated the use of gas-phase intra-molecular reactions facilitated by collisional activation to investigate bi-molecular reactions with inherent low reactivity. Reactions between sulfinyl radicals (-SO˙) toward free thiol (-SH) were employed as a model system. A new reaction channel, i.e. sulfinyl exchange with thiol, was observed under beam-type collision-induced dissociation (CID), which was not detectable from traditional ion/molecule reactions.