Carthamin synthase of Carthamus tinctorius L.

Carthamin, a dimeric quinochalcone that is only sparingly soluble in water, is produced from yellow-orange petals of fully blooming safflower Carthamus tinctorius L. florets. Carthamin is a historic red colorant, which has been used worldwide for more than 4000 years and is the major component of Japanese beni used for dyeing textiles, cosmetics, and food colorants. However, biosynthetic pathway of carthamin has long remained a mystery, in which carthamin was proposed to be produced from precarthamin, a water-soluble quinochalcone, via a single enzymatic process. Here we identified the gene coding for the enzyme responsible for the formation of carthamin from precarthamin, termed carthamin synthase, via enzyme purification and transcriptome analysis approaches.