Phytoene desaturase (lycopene-forming)


Phytoene desaturase are enzymes found in archaea, bacteria and fungi that are involved in carotenoid biosynthesis. They catalyze the conversion of colorless 15-cis-phytoene into a bright red lycopene in a biochemical pathway called the poly-trans pathway. The same process in plants and cyanobacteria utilizes four separate enzymes in a poly-cis pathway.

Biochemistry

Bacterial phytoene desaturases were shown to require FAD as a cofactor for their function. During the chemical reaction in total four additional double bonds are introduced into phytoene:

Applications

In 2000 it was discovered that the gene insertion of a bacterial phytoene desaturase into transgenic tomatoes increased the lycopene content without the need to alter several of the plants enzymes. This approach was later used in rice to increase its β-carotene content resulting in the Golden Rice project.