In Rhodopseudomonas capsulata and Rubrivivax gelatinosus the enzyme is involved in biosynthesis of spheroidene [1,2,3]. In Rubrivivax gelatinosus the enzyme also catalyses the methylation of demethylspirilloxanthin to spirilloxanthin and the methylation of 3,4-didehydrorhodopin to anhydrorhodovibrin [2].