Fig. 7: Frequency of reactions across the seven main EC classes.
From: MechFind: a computational framework for de novo prediction of enzyme mechanisms

a The 15,210 reactions used from the Rhea database and b The 23,504 reactions used from the MetaNetX database. The “NA“ category includes reactions without an assigned EC number. Both databases are dominated by oxidoreductases (EC 1), transferases (EC 2), and hydrolases (EC 3), reflecting the prevalence of these catalytic functions in known metabolism.