Annotations to Reactions

Once a genome has been annotated with functional roles, we can determine what chemical reactions those roles implement. For example, in B. subtilis, we annotated a gene with the functional role "Pyruvate kinase (EC" or "Enolase". This, of course, maps directly to a reaction, converting Phosphoenolpyruvate into Pyruvate and generating one ATP in the process. Other reaction assignments are, of course, more difficult, requiring the presence of multiple genes to form enzyme complexes. Additionally, since chemically many reactions can proceed in either direction we must determine which directions are implemented by the organism.