ENZYMATIC 10-HYDROXYLATION AND 10-O-METHYLATION OF DIHYDROSANGUINARINE IN DIHYDROCHELIRUBINE FORMATION BY ESCHSCHOLTZIA

Two new enzymes involved in benzophenanthridine alkaloid biosynthesis, dihydrosanguinarine-10-hydroxylase and 10-hydroxydihydrosanguinarine-10-O-methyltransferase, have been found in cell-free extracts derived from Eschscholtzia californica cell suspension cultures. The hydroxylase is a microsome-associated, cytochrome P-450-dependent monooxygenase which acts specifically at C-10 of dihydrosanguinarine. The methyltransferase, enriched 60-fold and partially characterized, methylates only the hydroxyl moiety at C-10 to form dihydrochelirubine. Both enzymes were found to be highly substrate specific.