Table 2. Enzyme Classification: Main classes of enzymes in EC system.
First EC digitEnzyme classReaction type
1.OxidoreductasesOxidation/reduction
2.TransferasesAtom/group transfer (excluding other classes)
3.HydrolasesHydrolysis
4.LyasesGroup removal (excluding 3.)
5.IsomerasesIsomerization
6.LigasesJoining of molecules linked to the breakage of a pyrophosphate bond