1. Oxidoreductases

 2. Transferases

 3. Hydrolases

   3.1  Acting on ester bonds

   3.2  Glycosylases

   3.3  Acting on ether bonds

   3.4  Acting on peptide bonds (peptidases)

   3.5  Acting on carbon-nitrogen bonds, other than peptide bonds

   3.6  Acting on acid anhydrides

   3.7  Acting on carbon-carbon bonds

     3.7.1  In ketonic substances

       3.7.1.1  oxaloacetase

       3.7.1.2  fumarylacetoacetase

       3.7.1.3  kynureninase

       3.7.1.4  phloretin hydrolase

       3.7.1.5  acylpyruvate hydrolase

       3.7.1.6  acetylpyruvate hydrolase

       3.7.1.7  beta-diketone hydrolase

       3.7.1.8  2,6-dioxo-6-phenylhexa-3-enoate hydrolase

       3.7.1.9  2-hydroxymuconate-6-semialdehyde hydrolase

       3.7.1.10  cyclohexane-1,3-dione hydrolase

       3.7.1.11  cyclohexane-1,2-dione hydrolase

       3.7.1.12  cobalt-precorrin 5A hydrolase

       3.7.1.13  2-hydroxy-6-oxo-6-(2-aminophenyl)hexa-2,4-dienoate hydrolase

       3.7.1.14  2-hydroxy-6-oxonona-2,4-dienedioate hydrolase

       3.7.1.17  4,5:9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-diene-4-oate hydrolase

       3.7.1.18  6-oxocamphor hydrolase

       3.7.1.19  2,6-dihydroxypseudooxynicotine hydrolase

       3.7.1.20  3-fumarylpyruvate hydrolase

       3.7.1.21  6-oxocyclohex-1-ene-1-carbonyl-CoA hydratase

       3.7.1.22  3D-(3,5/4)-trihydroxycyclohexane-1,2-dione acylhydrolase (ring-opening)

       3.7.1.23  maleylpyruvate hydrolase

       3.7.1.24  2,4-diacetylphloroglucinol hydrolase

       3.7.1.25  2-hydroxy-6-oxohepta-2,4-dienoate hydrolase

       3.7.1.26  2,4-didehydro-3-deoxy-L-rhamnonate hydrolase

       3.7.1.28  3-oxoisoapionate-4-phosphate transcarboxylase/hydrolase

   3.8  Acting on halide bonds

   3.9  Acting on phosphorus-nitrogen bonds

   3.10  Acting on sulfur-nitrogen bonds

   3.11  Acting on carbon-phosphorus bonds

   3.12  Acting on sulfur-sulfur bonds

   3.13  Acting on carbon-sulfur bonds

 4. Lyases

 5. Isomerases

 6. Ligases

 7. Translocases