Jasmonate-induced epoxidation of tabersonine by a cytochrome P-450 in hairy root cultures of Catharanthus roseus

Methyl jasmonate, a chemical inducer of secondary metabolism, was shown to promote tabersonine 2 biosynthesis in hairy root cultures of Catharanthus roseus. Tabersonine 6,7-epoxidase activity was detected in total protein extract of jasmonate-induced hairy root cultures using labeled 14C-tabersonine 2. This enzyme converted tabersonine 2 to lochnericine 3 by selective epoxidation at positions 6 and 7 via a reaction dependent on NADPH and molecular oxygen. Carbon monoxide, clotrimazole, miconazole, and cytochrome C were shown to be strong inhibitors of the enzyme. The activity was found in microsomes, indicating that tabersonine 6,7-epoxidase was a cytochrome P-450-dependent monooxygenase. Methyl jasmonate promoted tabersonine biosynthesis in hairy root cultures of Catharanthus roseus. Tabersonine 6,7-epoxidase activity in microsomes was inhibited by carbon monoxide, clotrimazole, miconazole, and cytochrome C, indicating that the enzyme was a cytochrome P-450-dependent monooxygenase.