ô-Amyrin synthase (, SlTTS2 (gene)) is an enzyme with systematic name (3S)-2,3-epoxy-2,3-dihydrosqualene mutase (cyclizing, delta-amyrin-forming). This enzyme catalyses the following chemical reaction
The enzyme from tomato (Solanum lycopersicum) gives delta-amyrin, alpha-amyrin, beta-amyrin.