Trifluoroethanol-induced conformational changes in α- and β-neoendorphins monitored using hydrogen/deuterium exchange mass spectrometry and circular dichroism spectroscopy

▶ H/D exchange, coupled with ESI-MS, can be effectively used to monitor changes in conformational structures of small size peptides. ▶ In pure water, α-neoendorphin and β-neoenorphin both exist as random coil open structures. ▶ Both peptides acquire secondary structural elements in the [water + trifluoroethanol] mixed solvent system.