Geraniol 10-hydroxylase11The nucleotide sequence newly reported in this paper has been deposited in the GenBank/EMBL data banks with the accession number AJ251269, a cytochrome P450 enzyme involved in terpenoid indole alkaloid biosynthesis

Geraniol 10-hydroxylase (G10H) is a cytochrome P450 monooxygenase involved in the biosynthesis of iridoid monoterpenoids and several classes of monoterpenoid alkaloids found in a diverse range of plant species. Catharanthus roseus(Madagascar periwinkle) contains monoterpenoid indole alkaloids, several of which are pharmaceutically important. Vinblastine and vincristine, for example, find widespread use as anti-cancer drugs. G10H is thought to play a key regulatory role in terpenoid indole alkaloid biosynthesis. We purified G10H from C. roseuscells. Using degenerate PCR primers based on amino acid sequence information we cloned the corresponding cDNA. The encoded CYP76B6 protein has G10H activity when expressed in C. roseusand yeast cells. The stress hormone methyljasmonate strongly induced G10hgene expression coordinately with other terpenoid indole alkaloid biosynthesis genes in a C. roseuscell culture.