1. Oxidoreductases

 2. Transferases

   2.1  Transferring one-carbon groups

   2.2  Transferring aldehyde or ketonic groups

   2.3  Acyltransferases

   2.4  Glycosyltransferases

   2.5  Transferring alkyl or aryl groups, other than methyl groups

   2.6  Transferring nitrogenous groups

   2.7  Transferring phosphorus-containing groups

     2.7.1  Phosphotransferases with an alcohol group as acceptor

     2.7.2  Phosphotransferases with a carboxy group as acceptor

     2.7.3  Phosphotransferases with a nitrogenous group as acceptor

     2.7.4  Phosphotransferases with a phosphate group as acceptor

     2.7.6  Diphosphotransferases

       2.7.6.1  ribose-phosphate diphosphokinase

       2.7.6.2  thiamine diphosphokinase

       2.7.6.3  2-amino-4-hydroxy-6-hydroxymethyldihydropteridine diphosphokinase

       2.7.6.4  nucleotide diphosphokinase

       2.7.6.5  GTP diphosphokinase

     2.7.7  Nucleotidyltransferases

     2.7.8  Transferases for other substituted phosphate groups

     2.7.9  Phosphotransferases with paired acceptors

     2.7.10  Protein-tyrosine kinases

     2.7.11  Protein-serine/threonine kinases

     2.7.12  Dual-specificity kinases (those acting on Ser/Thr and Tyr residues)

     2.7.13  Protein-histidine kinases

     2.7.14  Protein-arginine kinases

     2.7.99  Other protein kinases

   2.8  Transferring sulfur-containing groups

   2.9  Transferring selenium-containing groups

   2.10  Transferring molybdenum- or tungsten-containing groups

 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

     3.5.1  In linear amides

     3.5.2  In cyclic amides

     3.5.3  In linear amidines

     3.5.4  In cyclic amidines

       3.5.4.1  cytosine deaminase

       3.5.4.2  adenine deaminase

       3.5.4.3  guanine deaminase

       3.5.4.4  adenosine deaminase

       3.5.4.5  cytidine deaminase

       3.5.4.6  AMP deaminase

       3.5.4.7  ADP deaminase

       3.5.4.8  aminoimidazolase

       3.5.4.9  methenyltetrahydrofolate cyclohydrolase

       3.5.4.10  IMP cyclohydrolase

       3.5.4.11  pterin deaminase

       3.5.4.12  dCMP deaminase

       3.5.4.13  dCTP deaminase

       3.5.4.15  guanosine deaminase

       3.5.4.16  GTP cyclohydrolase I

       3.5.4.17  adenosine-phosphate deaminase

       3.5.4.18  ATP deaminase

       3.5.4.19  phosphoribosyl-AMP cyclohydrolase

       3.5.4.20  pyrithiamine deaminase

       3.5.4.21  creatinine deaminase

       3.5.4.22  1-pyrroline-4-hydroxy-2-carboxylate deaminase

       3.5.4.23  blasticidin-S deaminase

       3.5.4.24  sepiapterin deaminase

       3.5.4.25  GTP cyclohydrolase II

       3.5.4.26  diaminohydroxyphosphoribosylaminopyrimidine deaminase

       3.5.4.27  methenyltetrahydromethanopterin cyclohydrolase

       3.5.4.28  S-adenosylhomocysteine deaminase

       3.5.4.29  GTP cyclohydrolase IIa

       3.5.4.30  dCTP deaminase (dUMP-forming)

       3.5.4.31  S-methyl-5'-thioadenosine deaminase

       3.5.4.32  8-oxoguanine deaminase

       3.5.4.33  tRNA(adenine34) deaminase

       3.5.4.34  tRNAAla(adenine37) deaminase

       3.5.4.35  tRNA(cytosine8) deaminase

       3.5.4.36  mRNA(cytosine6666) deaminase

       3.5.4.37  double-stranded RNA adenine deaminase

       3.5.4.38  single-stranded DNA cytosine deaminase

       3.5.4.39  GTP cyclohydrolase IV

       3.5.4.40  aminodeoxyfutalosine deaminase

       3.5.4.41  5'-deoxyadenosine deaminase

       3.5.4.42  N-isopropylammelide isopropylaminohydrolase

       3.5.4.43  hydroxydechloroatrazine ethylaminohydrolase

       3.5.4.44  ectoine hydrolase

       3.5.4.45  melamine deaminase

       3.5.4.46  cAMP deaminase

     3.5.5  In nitriles

     3.5.99  In other compounds

   3.6  Acting on acid anhydrides

   3.7  Acting on carbon-carbon bonds

   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