Discovering how pepper grows: IPB scientists clarify important step in piperine biosynthesis.
Piperine, the pungent principle of black pepper (Piper nigrum), was already identified 200 years ago, but its biosynthesis has not yet been elucidated. IPB scientists have now succeeded in taking an important step in this direction. With a combination of RNA sequencing and LC-MS-based analysis of substrate and product profiles, they identified a cytochrome P450 enzyme that catalyzes the characteristic methylenedioxy bridge formation in the aromatic part of piperine. The CYP719A37 enzyme is specifically produced in immature fruits of black pepper. The corresponding gene was expressed in yeast and tested for substrate specificity with a variety of aromatic potential precursor compounds. Accordingly, methlendioxy bridge formation was only detected when feruperic acid was used as a substrate; the corresponding product of the reaction could be identified as piperic acid.
Cytochrome P450 enzymes (CYPs) are heme-dependent monooxygenases that catalyze a variety of hydroxylation and monooxygenation reactions. They play an essential role in chemical modifications of all kinds of natural products, like terpenoids, phenylpropanoids, alkaloids, glucosinolates or cyanogenic glycosides. Besides the common reactions, CYPs also catalyze unusual reactions, such as the formation of methylenedioxy bridges or phenol coupling. The CYP719A37 enzyme characterized by the Halle researchers was discussed in terms of specificity, storage and phylogenetic origin.
