Biosynthesis of steroidal alkaloids in Solanaceae plants: Involvement of an aldehyde intermediate during C-26 amination

► Mechanism of C-26 amination during steroidal alkaloid biosynthesis was investigated. ► Deuterium labeled cholesterol and mevalonate were administered to Solanum lycopersicum, Solanum tuberosum and Solanum melongena. ► Two hydrogen atoms were eliminated from C-26 of cholesterol during steroidal alkaloid biosynthesis. ► It is proposed that the C-26 amination reaction proceeds via a transamination mechanism.