Exploration and utilization of novel aldoxime, nitrile, and nitro compounds metabolizing enzymes from plants and...

Aldoxime (R1R2C=NOH) and nitrile (R-C≡N) are nitrogen-containing compounds that are found in species representing all kingdoms of life. The enzymes discovered from the microbial "aldoxime-nitrile" pathway (aldoxime dehydratase, nitrile hydratase, amidase, and nitrilase) have been thoroughly studied because of their industrial importance. Although plants utilize cytochrome P450 monooxygenases to produce aldoxime and nitrile, many biosynthetic pathways are yet to be studied. Cyanogenic millipedes accumulate various nitrile compounds, such as mandelonitrile. However, no such aldoxime- and nitrile-metabolizing enzymes have been identified in millipedes. Here, I review the exploration of novel enzymes from plants and millipedes with characteristics distinct from those of microbial enzymes, the catalysis of industrially useful reactions, and applications of these enzymes for nitrile compound production.