Metal ions regulate terpenoid metabolism in insects
Max Planck scientists in Jena, Germany, have discovered an unusual regulation of enzymes that catalyze chain elongation in an important secondary metabolism, the terpenoid pathway. In the horseradish leaf beetle Phaedon cochleariae a single enzyme can trigger the production of two completely different substances depending on whether it is regulated by cobalt, manganese or magnesium ions: iridoids, which are defensive substances the larvae use to repel predators, or juvenile hormones, which control insect's development. Insects unlike plants do not have a large arsenal of the proteins called isoprenyl diphosphate synthases. Therefore they may have developed another efficient option to channel metabolites into the different directions of terpenoid metabolism by using metal ions for control.