7-deoxyloganin 7-hydroxylase in Lonicera japonica cell cultures

The activity of 7-deoxyloganin 7-hydroxylase, an enzyme catalyzing the conv ersion of 7-deoxyloganin into loganin, was detected in a microsomal prepara tion from the cell suspension cultures of Lonicera japonica. It was depende nt on NADPH and molecular oxygen. The enzymatic reaction was inhibited by c arbon monoxide as well as by several cytochrome P450 inhibitors, especially ketoconazole, indicating that the reaction was mediated by cytochrome P450 . The enzyme showed substrate specificity for 7-deoxyloganin. The K-m value s for 7-deoxyloganin and NADPH were estimated as 170 and 18 muM, respective ly. from Lineweaver-Burk plots. (C) 2001 Elsevier Science Ltd. All rights r eserved.