Chemical compounds that contains a CN functional group. Organic cyanides are usually called nitriles. Cyanogenesis is a defense process of several thousand plant species. (Some millipedes are able to exude toxic hydrogen cyanide as a defense). Hydroxynitrile lyase, a key enzyme of this process, cleaves a cyanohydrin into hydrocyanic acid and the corresponding aldehyde or ketone. The reverse reaction constitutes an important tool in biocatalysis. Building block for many inhibitors of enzymes