_EC 4.2.1.- Hydro-lyases. 1,375 PDB entries  
EC 4.-.-.- Lyases. [3,636 PDB entries]
EC 4.2.-.- Carbon-oxygen lyases. [1,771 PDB entries]
EC 4.2.1.- Hydro-lyases. [1,375 PDB entries]    
EC 4.2.1.1 Carbonate dehydratase. [589 PDB entries]
EC 4.2.1.2 Fumarate hydratase. [22 PDB entries]
EC 4.2.1.3 Aconitate hydratase. [21 PDB entries]
EC 4.2.1.4 Transferred entry: 4.2.1.3. [-]
EC 4.2.1.5 Arabinonate dehydratase. [-]
EC 4.2.1.6 Galactonate dehydratase. [2 PDB entries]
EC 4.2.1.7 Altronate dehydratase. [-]
EC 4.2.1.8 Mannonate dehydratase. [32 PDB entries]
EC 4.2.1.9 Dihydroxy-acid dehydratase. [-]
EC 4.2.1.10 3-dehydroquinate dehydratase. [90 PDB entries]
EC 4.2.1.11 Phosphopyruvate hydratase. [62 PDB entries]
EC 4.2.1.12 Phosphogluconate dehydratase. [1 PDB entries]
EC 4.2.1.13 Transferred entry: 4.3.1.17. [-]
EC 4.2.1.14 Transferred entry: 4.3.1.18. [-]
EC 4.2.1.15 Transferred entry: 4.4.1.1. [-]
EC 4.2.1.16 Transferred entry: 4.3.1.19. [-]
EC 4.2.1.17 Enoyl-CoA hydratase. [41 PDB entries]
EC 4.2.1.18 Methylglutaconyl-CoA hydratase. [3 PDB entries]
EC 4.2.1.19 Imidazoleglycerol-phosphate dehydratase. [11 PDB entries]
EC 4.2.1.20 Tryptophan synthase. [84 PDB entries]
EC 4.2.1.21 Transferred entry: 4.2.1.22. [-]
EC 4.2.1.22 Cystathionine beta-synthase. [16 PDB entries]
EC 4.2.1.23 Deleted entry. [-]
EC 4.2.1.24 Porphobilinogen synthase. [40 PDB entries]
EC 4.2.1.25 L-arabinonate dehydratase. [-]
EC 4.2.1.26 Transferred entry: 4.3.1.9. [-]
EC 4.2.1.27 Acetylenecarboxylate hydratase. [-]
EC 4.2.1.28 Propanediol dehydratase. [8 PDB entries]
EC 4.2.1.29 Transferred entry: 4.99.1.6. [-]
EC 4.2.1.30 Glycerol dehydratase. [3 PDB entries]
EC 4.2.1.31 Maleate hydratase. [3 PDB entries]
EC 4.2.1.32 L(+)-tartrate dehydratase. [-]
EC 4.2.1.33 3-isopropylmalate dehydratase. [9 PDB entries]
EC 4.2.1.34 (S)-2-methylmalate dehydratase. [-]
EC 4.2.1.35 (R)-2-methylmalate dehydratase. [3 PDB entries]
EC 4.2.1.36 Homoaconitate hydratase. [-]
EC 4.2.1.37 Transferred entry: 3.3.2.4. [-]
EC 4.2.1.38 Transferred entry: 4.3.1.20. [-]
EC 4.2.1.39 Gluconate dehydratase. [16 PDB entries]
EC 4.2.1.40 Glucarate dehydratase. [17 PDB entries]
EC 4.2.1.41 5-dehydro-4-deoxyglucarate dehydratase. [-]
EC 4.2.1.42 Galactarate dehydratase. [6 PDB entries]
EC 4.2.1.43 2-dehydro-3-deoxy-L-arabinonate dehydratase. [2 PDB entries]
EC 4.2.1.44 Myo-inosose-2 dehydratase. [1 PDB entries]
EC 4.2.1.45 CDP-glucose 4,6-dehydratase. [1 PDB entries]
EC 4.2.1.46 dTDP-glucose 4,6-dehydratase. [11 PDB entries]
EC 4.2.1.47 GDP-mannose 4,6-dehydratase. [7 PDB entries]
EC 4.2.1.48 D-glutamate cyclase. [-]
EC 4.2.1.49 Urocanate hydratase. [6 PDB entries]
EC 4.2.1.50 Pyrazolylalanine synthase. [-]
EC 4.2.1.51 Prephenate dehydratase. [5 PDB entries]
EC 4.2.1.52 Transferred entry: 4.3.3.7. [6 PDB entries]
EC 4.2.1.53 Oleate hydratase. [-]
EC 4.2.1.54 Lactoyl-CoA dehydratase. [3 PDB entries]
EC 4.2.1.55 3-hydroxybutyryl-CoA dehydratase. [1 PDB entries]
EC 4.2.1.56 Itaconyl-CoA hydratase. [-]
EC 4.2.1.57 Isohexenylglutaconyl-CoA hydratase. [-]
EC 4.2.1.58 Transferred entry: 4.2.1.59. [-]
EC 4.2.1.59 3-hydroxyacyl-[acyl-carrier-protein] dehydratase. [42 PDB entries]
EC 4.2.1.60 Transferred entry: 4.2.1.59. [-]
EC 4.2.1.61 Transferred entry: 4.2.1.59. [-]
EC 4.2.1.62 5-alpha-hydroxysteroid dehydratase. [-]
EC 4.2.1.63 Transferred entry: 3.3.2.9 and 3.3.2.10. [-]
EC 4.2.1.64 Transferred entry: 3.3.2.9 and 3.3.2.10. [-]
EC 4.2.1.65 3-cyanoalanine hydratase. [-]
EC 4.2.1.66 Cyanide hydratase. [-]
EC 4.2.1.67 D-fuconate dehydratase. [-]
EC 4.2.1.68 L-fuconate dehydratase. [5 PDB entries]
EC 4.2.1.69 Cyanamide hydratase. [-]
EC 4.2.1.70 Pseudouridylate synthase. [1 PDB entries]
EC 4.2.1.71 Transferred entry: 4.2.1.27. [-]
EC 4.2.1.72 Transferred entry: 4.1.1.78. [-]
EC 4.2.1.73 Protoaphin-aglucone dehydratase (cyclizing). [-]
EC 4.2.1.74 Long-chain-enoyl-CoA hydratase. [-]
EC 4.2.1.75 Uroporphyrinogen-III synthase. [7 PDB entries]
EC 4.2.1.76 UDP-glucose 4,6-dehydratase. [-]
EC 4.2.1.77 Trans-L-3-hydroxyproline dehydratase. [-]
EC 4.2.1.78 (S)-norcoclaurine synthase. [2 PDB entries]
EC 4.2.1.79 2-methylcitrate dehydratase. [1 PDB entries]
EC 4.2.1.80 2-oxopent-4-enoate hydratase. [2 PDB entries]
EC 4.2.1.81 D(-)-tartrate dehydratase. [3 PDB entries]
EC 4.2.1.82 Xylonate dehydratase. [-]
EC 4.2.1.83 4-oxalmesaconate hydratase. [-]
EC 4.2.1.84 Nitrile hydratase. [28 PDB entries]
EC 4.2.1.85 Dimethylmaleate hydratase. [-]
EC 4.2.1.86 Transferred entry: 4.2.1.98. [-]
EC 4.2.1.87 Octopamine dehydratase. [-]
EC 4.2.1.88 (R)-synephrine. [-]
EC 4.2.1.89 Transferred entry: 2.8.3.21 and 4.2.1.149. [-]
EC 4.2.1.90 L-rhamnonate dehydratase. [9 PDB entries]
EC 4.2.1.91 Arogenate dehydratase. [1 PDB entries]
EC 4.2.1.92 Hydroperoxide dehydratase. [16 PDB entries]
EC 4.2.1.93 ATP-dependent NAD(P)H-hydrate dehydratase. [-]
EC 4.2.1.94 Scytalone dehydratase. [8 PDB entries]
EC 4.2.1.95 Kievitone hydratase. [-]
EC 4.2.1.96 4a-hydroxytetrahydrobiopterin dehydratase. [12 PDB entries]
EC 4.2.1.97 Phaseollidin hydratase. [-]
EC 4.2.1.98 16-alpha-hydroxyprogesterone dehydratase. [-]
EC 4.2.1.99 2-methylisocitrate dehydratase. [1 PDB entries]
EC 4.2.1.100 Cyclohexa-1,5-dienecarbonyl-CoA hydratase. [-]
EC 4.2.1.101 Trans-feruloyl-CoA hydratase. [3 PDB entries]
EC 4.2.1.102 Transferred entry: 4.2.1.100. [-]
EC 4.2.1.103 Cyclohexyl-isocyanide hydratase. [-]
EC 4.2.1.104 Cyanase. [8 PDB entries]
EC 4.2.1.105 2-hydroxyisoflavanone dehydratase. [-]
EC 4.2.1.106 Bile-acid 7-alpha-dehydratase. [4 PDB entries]
EC 4.2.1.107 3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholest-24-enoyl-CoA [4 PDB entries]
EC 4.2.1.108 Ectoine synthase. [-]
EC 4.2.1.109 Methylthioribulose 1-phosphate dehydratase. [2 PDB entries]
EC 4.2.1.110 Aldos-2-ulose dehydratase. [3 PDB entries]
EC 4.2.1.111 1,5-anhydro-D-fructose dehydratase. [-]
EC 4.2.1.112 Acetylene hydratase. [1 PDB entries]
EC 4.2.1.113 o-succinylbenzoate synthase. [6 PDB entries]
EC 4.2.1.114 Methanogen homoaconitase. [2 PDB entries]
EC 4.2.1.115 UDP-N-acetylglucosamine 4,6-dehydratase (inverting). [5 PDB entries]
EC 4.2.1.116 3-hydroxypropionyl-CoA dehydratase. [-]
EC 4.2.1.117 2-methylcitrate dehydratase (2-methyl-trans-aconitate forming). [-]
EC 4.2.1.118 3-dehydroshikimate dehydratase. [1 PDB entries]
EC 4.2.1.119 Enoyl-CoA hydratase 2. [9 PDB entries]
EC 4.2.1.120 4-hydroxybutanoyl-CoA dehydratase. [1 PDB entries]
EC 4.2.1.121 Colneleate synthase. [-]
EC 4.2.1.122 Tryptophan synthase (indole-salvaging). [-]
EC 4.2.1.123 Tetrahymanol synthase. [-]
EC 4.2.1.124 Arabidiol synthase. [-]
EC 4.2.1.125 Dammarenediol Ii synthase. [-]
EC 4.2.1.126 N-acetylmuramic acid 6-phosphate etherase. [3 PDB entries]
EC 4.2.1.127 Linalool dehydratase. [-]
EC 4.2.1.128 Lupan-3-beta,20-diol synthase. [-]
EC 4.2.1.129 Squalene--hopanol cyclase. [16 PDB entries]
EC 4.2.1.130 D-lactate dehydratase. [5 PDB entries]
EC 4.2.1.131 Carotenoid 1,2-hydratase. [-]
EC 4.2.1.132 2-hydroxyhexa-2,4-dienoate hydratase. [-]
EC 4.2.1.133 Copal-8-ol diphosphate hydratase. [-]
EC 4.2.1.134 Very-long-chain (3R)-3-hydroxyacyl-CoA dehydratase. [-]
EC 4.2.1.135 UDP-N-acetylglucosamine 4,6-dehydratase (configuration-retaining). [-]
EC 4.2.1.136 ADP-dependent NAD(P)H-hydrate dehydratase. [35 PDB entries]
EC 4.2.1.137 Sporulenol synthase. [-]
EC 4.2.1.138 (+)-caryolan-1-ol synthase. [-]
EC 4.2.1.139 Medicarpin synthase. [-]
EC 4.2.1.140 Gluconate/galactonate dehydratase. [-]
EC 4.2.1.141 2-dehydro-3-deoxy-D-arabinonate dehydratase. [-]
EC 4.2.1.142 5'-oxoaverantin cyclase. [-]
EC 4.2.1.143 Versicolorin B synthase. [-]
EC 4.2.1.144 3-amino-5-hydroxybenzoate synthase. [2 PDB entries]
EC 4.2.1.145 Capreomycidine synthase. [-]
EC 4.2.1.146 L-galactonate dehydratase. [-]
EC 4.2.1.147 5,6,7,8-tetrahydromethanopterin hydro-lyase. [2 PDB entries]
EC 4.2.1.148 2-methylfumaryl-CoA hydratase. [1 PDB entries]
EC 4.2.1.149 Crotonobetainyl-CoA hydratase. [-]
EC 4.2.1.150 Short-chain-enoyl-CoA hydratase. [-]
EC 4.2.1.151 Chorismate dehydratase. [1 PDB entries]
EC 4.2.1.152 Hydroperoxy icosatetraenoate dehydratase. [-]
EC 4.2.1.153 3-methylfumaryl-CoA hydratase. [-]
EC 4.2.1.154 Tetracenomycin F2 cyclase. [1 PDB entries]
EC 4.2.1.n1 Transferred entry: 4.2.1.126. [-]
EC 4.2.1.n2 Transferred entry: 4.2.1.134. [-]

[-] signifies that there are no PDB entries for the given enzyme subclass