Multidimensional Reaction Dynamics Reveal How the Enzyme TcTS Suppresses Competing Side Reactions and Their Side Products. The suppression of competing reactions that lead to side products is one of the key mechanistic actions defining enzyme catalysis. The transfer of sialic acid (SA) in a water solution is susceptible to two competing side reactions, but a single product is the outcome in the glycosylation and deglycosylation.