This list contains a list of EC numbers for the sixth group, EC 6, ligases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology.

EC 6.1: Forming Carbon-Oxygen Bonds[edit]

EC 6.1.1: Ligases Forming Aminoacyl-tRNA and Related Compounds (Aminoacyl tRNA synthetase)[edit]

• 
  EC 6.1.1.1: tyrosine-tRNA ligase
  


• 
  EC 6.1.1.2: tryptophan-tRNA ligase
  


• 
  EC 6.1.1.3: threonine-tRNA ligase
  


• 
  EC 6.1.1.4: leucine-tRNA ligase
  


• 
  EC 6.1.1.5: isoleucine-tRNA ligase
  


• 
  EC 6.1.1.6: lysine-tRNA ligase
  


• 
  EC 6.1.1.7: alanine-tRNA ligase
  


• 
  EC 6.1.1.8: Deleted


• 
  EC 6.1.1.9: valine-tRNA ligase
  


• 
  EC 6.1.1.10: methionine-tRNA ligase
  


• 
  EC 6.1.1.11: serine-tRNA ligase
  


• 
  EC 6.1.1.12: aspartate-tRNA ligase
  


• 
  EC 6.1.1.13: D-alanine-poly(phosphoribitol) ligase
  


• 
  EC 6.1.1.14: glycine-tRNA ligase
  


• 
  EC 6.1.1.15: proline-tRNA ligase
  


• 
  EC 6.1.1.16: cysteine-tRNA ligase
  


• 
  EC 6.1.1.17: glutamate-tRNA ligase
  


• 
  EC 6.1.1.18: glutamine-tRNA ligase
  


• 
  EC 6.1.1.19: arginine-tRNA ligase
  


• 
  EC 6.1.1.20: phenylalanine-tRNA ligase
  


• 
  EC 6.1.1.21: histidine-tRNA ligase
  


• 
  EC 6.1.1.22: asparagine-tRNA ligase
  


• 
  EC 6.1.1.23: aspartate-tRNAAsn ligase
  


• 
  EC 6.1.1.24: glutamate-tRNAGln ligase
  


• 
  EC 6.1.1.25: lysine-tRNAPyl ligase
  


• 
  EC 6.1.1.26: pyrrolysine—tRNAPyl ligase
  


• 
  EC 6.1.1.27: O-phospho-L-serine—tRNA ligase
  

EC 6.1.2: Acid—alcohol ligases (ester synthases)[edit]

• 
  EC 6.1.2.1: D-alanine—(R)-lactate ligase
  

EC 6.2: Forming Carbon-Sulfur Bonds[edit]

EC 6.2.1: Acid-Thiol Ligases[edit]

• 
  EC 6.2.1.1: acetate-CoA ligase
  


• 
  EC 6.2.1.2: butyrate-CoA ligase
  


• 
  EC 6.2.1.3: long-chain-fatty-acid-CoA ligase
  


• 
  EC 6.2.1.4: succinate-CoA ligase (GDP-forming)
  


• 
  EC 6.2.1.5: succinate-CoA ligase (ADP-forming)
  


• 
  EC 6.2.1.6: glutarate-CoA ligase
  


• 
  EC 6.2.1.7: cholate-CoA ligase
  


• 
  EC 6.2.1.8: oxalate-CoA ligase
  


• 
  EC 6.2.1.9: malate-CoA ligase
  


• 
  EC 6.2.1.10: acid-CoA ligase (GDP-forming)
  


• 
  EC 6.2.1.11: biotin-CoA ligase
  


• 
  EC 6.2.1.12: 4-coumarate-CoA ligase
  


• 
  EC 6.2.1.13: acetate-CoA ligase (ADP-forming)
  


• 
  EC 6.2.1.14: 6-carboxyhexanoate-CoA ligase
  


• 
  EC 6.2.1.15: arachidonate-CoA ligase
  


• 
  EC 6.2.1.16: acetoacetate-CoA ligase
  


• 
  EC 6.2.1.17: propionate-CoA ligase
  


• 
  EC 6.2.1.18: citrate-CoA ligase
  


• 
  EC 6.2.1.19: long-chain-fatty-acid-luciferin-component ligase
  


• 
  EC 6.2.1.20: long-chain-fatty-acid-(acyl-carrier-protein) ligase
  


• 
  EC 6.2.1.21: Covered by EC 6.2.1.30
  


• 
  EC 6.2.1.22: (citrate (pro-3S)-lyase) ligase
  


• 
  EC 6.2.1.23: dicarboxylate-CoA ligase
  


• 
  EC 6.2.1.24: phytanate-CoA ligase
  


• 
  EC 6.2.1.25: benzoate-CoA ligase
  


• 
  EC 6.2.1.26: o-succinylbenzoate-CoA ligase
  


• 
  EC 6.2.1.27: 4-hydroxybenzoate-CoA ligase
  


• 
  EC 6.2.1.28: 3a,7a-dihydroxy-5b-cholestanate-CoA ligase
  


• 
  EC 6.2.1.29: Deleted, now EC 6.2.1.7
  


• 
  EC 6.2.1.30: phenylacetate-CoA ligase
  


• 
  EC 6.2.1.31: 2-furoate-CoA ligase
  


• 
  EC 6.2.1.32: anthranilate-CoA ligase
  


• 
  EC 6.2.1.33: 4-chlorobenzoate-CoA ligase
  


• 
  EC 6.2.1.34: trans-feruloyl-CoA synthase
  


• 
  EC 6.2.1.35: ACP-SH:acetate ligase
  


• 
  EC 6.2.1.36: 3-hydroxypropionyl-CoA synthase
  


• 
  EC 6.2.1.37: 3-hydroxybenzoate—CoA ligase
  


• 
  EC 6.2.1.38: (2,2,3-trimethyl-5-oxocyclopent-3-enyl)acetyl-CoA synthase
  


• 
  EC 6.2.1.39: (butirosin acyl-carrier protein)—L-glutamate ligase
  

EC 6.3: Forming Carbon-Nitrogen Bonds[edit]

EC 6.3.1: Acid-Ammonia (or Amine) Ligases (Amide Synthases)[edit]

• 
  EC 6.3.1.1: aspartate-ammonia ligase
  


• 
  EC 6.3.1.2: glutamate-ammonia ligase
  


• 
  EC 6.3.1.3: Now EC 6.3.4.13
  


• 
  EC 6.3.1.4: aspartate-ammonia ligase (ADP-forming)
  


• 
  EC 6.3.1.5: NAD+ synthase
  


• 
  EC 6.3.1.6: glutamate-ethylamine ligase
  


• 
  EC 6.3.1.7: 4-methyleneglutamate-ammonia ligase
  


• 
  EC 6.3.1.8: glutathionylspermidine synthase
  


• 
  EC 6.3.1.9: trypanothione synthase
  


• 
  EC 6.3.1.10: adenosylcobinamide-phosphate synthase
  


• 
  EC 6.3.1.11: glutamate-putrescine ligase
  


• 
  EC 6.3.1.12: D-aspartate ligase
  


• 
  EC 6.3.1.13: L-cysteine:1D-myo-inositol 2-amino-2-deoxy-alpha-D-glucopyranoside ligase
  


• 
  EC 6.3.1.14: diphthine—ammonia ligase
  

EC 6.3.2: Acid-Amino-Acid Ligases (Peptide Synthases)[edit]

• 
  EC 6.3.2.1: pantoate-b-alanine ligase
  


• 
  EC 6.3.2.2: glutamate-cysteine ligase
  


• 
  EC 6.3.2.3: glutathione synthase
  


• 
  EC 6.3.2.4: D-alanine-D-alanine ligase
  


• 
  EC 6.3.2.5: phosphopantothenate-cysteine ligase
  


• 
  EC 6.3.2.6: phosphoribosylaminoimidazolesuccinocarboxamide synthase
  


• 
  EC 6.3.2.7: UDP-N-acetylmuramoyl-L-alanyl-D-glutamate-L-lysine ligase
  


• 
  EC 6.3.2.8: UDP-N-acetylmuramate-L-alanine ligase
  


• 
  EC 6.3.2.9: UDP-N-acetylmuramoylalanine-D-glutamate ligase
  


• 
  EC 6.3.2.10: UDP-N-acetylmuramoylalanyl-tripeptide-D-alanyl-D-alanine ligase
  


• 
  EC 6.3.2.11: carnosine synthase
  


• 
  EC 6.3.2.12: dihydrofolate synthase
  


• 
  EC 6.3.2.13: UDP-N-acetylmuramoylalanyl-D-glutamate-2,6-diamino-pimelate ligase
  


• 
  EC 6.3.2.14: 2,3-dihydroxybenzoate-serine ligase
  


• 
  EC 6.3.2.15: Deleted, due to EC 6.3.2.10
  


• 
  EC 6.3.2.16: D-alanine-alanyl-poly(glycerolphosphate) ligase
  


• 
  EC 6.3.2.17: tetrahydrofolate synthase
  


• 
  EC 6.3.2.18: g-glutamylhistamine synthase
  


• 
  EC 6.3.2.19: ubiquitin-protein ligase
  


• 
  EC 6.3.2.20: indoleacetate-lysine synthetase
  


• 
  EC 6.3.2.21: ubiquitin-calmodulin ligase
  


• 
  EC 6.3.2.22: Now EC 6.3.1.14
  


• 
  EC 6.3.2.23: homoglutathione synthase
  


• 
  EC 6.3.2.24: tyrosine-arginine ligase
  


• 
  EC 6.3.2.25: tubulin-tyrosine ligase
  


• 
  EC 6.3.2.26: N-(5-amino-5-carboxypentanoyl)-L-cysteinyl-D-valine synthase
  


• 
  EC 6.3.2.27: The activity is covered by two independent enzymes, EC 6.3.2.38 N²-citryl-N⁶-acetyl-N⁶-hydroxylysine synthase, and EC 6.3.2.39, aerobactin synthase


• 
  EC 6.3.2.28: L-amino-acid alpha-ligase
  


• 
  EC 6.3.2.29: cyanophycin synthase (L-aspartate-adding)
  


• 
  EC 6.3.2.30: cyanophycin synthase (L-arginine-adding)
  


• 
  EC 6.3.2.31: coenzyme F420-0:L-glutamate ligase
  


• 
  EC 6.3.2.32: coenzyme gamma-F420-2:alpha-L-glutamate ligase
  


• 
  EC 6.3.2.33: tetrahydrosarcinapterin synthase
  


• 
  EC 6.3.2.34: coenzyme F420-1:gamma-L-glutamate ligase
  


• 
  EC 6.3.2.35: D-alanine---D-serine ligase
  


• 
  EC 6.3.2.36: 4-phosphopantoate---beta-alanine ligase
  


• 
  EC 6.3.2.37: UDP-N-acetylmuramoyl-L-alanyl-D-glutamate---D-lysine ligase
  


• 
  EC 6.3.2.38: N2-citryl-N6-acetyl-N6-hydroxylysine synthase
  


• 
  EC 6.3.2.39: aerobactin synthase
  

EC 6.3.3: Cyclo-Ligases[edit]

• 
  EC 6.3.3.1: phosphoribosylformylglycinamidine cyclo-ligase
  


• 
  EC 6.3.3.2: 5-formyltetrahydrofolate cyclo-ligase
  


• 
  EC 6.3.3.3: dethiobiotin synthase
  


• 
  EC 6.3.3.4: (carboxyethyl)arginine b-lactam-synthase
  

EC 6.3.4: Other Carbon-Nitrogen Ligases[edit]

• 
  EC 6.3.4.1: GMP synthase. Now included in EC 6.3.5.2, GMP synthase (glutamine—hydrolysing).


• 
  EC 6.3.4.2: CTP synthase
  


• 
  EC 6.3.4.3: formate-tetrahydrofolate ligase
  


• 
  EC 6.3.4.4: adenylosuccinate synthase
  


• 
  EC 6.3.4.5: argininosuccinate synthase
  


• 
  EC 6.3.4.6: urea carboxylase
  


• 
  EC 6.3.4.7: ribose-5-phosphate-ammonia ligase
  


• 
  EC 6.3.4.8: imidazoleacetate-phosphoribosyldiphosphate ligase
  


• 
  EC 6.3.4.9: biotin-(methylmalonyl-CoA-carboxytransferase) ligase
  


• 
  EC 6.3.4.10: biotin-(propionyl-CoA-carboxylase (ATP-hydrolysing)) ligase
  


• 
  EC 6.3.4.11: biotin-(methylcrotonoyl-CoA-carboxylase) ligase
  


• 
  EC 6.3.4.12: glutamate-methylamine ligase
  


• 
  EC 6.3.4.13: phosphoribosylamine-glycine ligase
  


• 
  EC 6.3.4.14: biotin carboxylase
  


• 
  EC 6.3.4.15: biotin-(acetyl-CoA-carboxylase) ligase
  


• 
  EC 6.3.4.16: carbamoyl-phosphate synthase (ammonia)
  


• 
  EC 6.3.4.17: formate-dihydrofolate ligase
  


• 
  EC 6.3.4.18: 5-(carboxyamino)imidazole ribonucleotide synthase
  


• 
  EC 6.3.4.19: tRNAIle-lysidine synthase
  


• 
  EC 6.3.4.20: 7-cyano-7-deazaguanine synthase
  


• 
  EC 6.3.4.21: nicotinate phosphoribosyltransferase
  

EC 6.3.5: Carbon-Nitrogen Ligases with Glutamine as Amido-N-Donor[edit]

• 
  EC 6.3.5.1: NAD+ synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.2: GMP synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.3: phosphoribosylformylglycinamidine synthase
  


• 
  EC 6.3.5.4: asparagine synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.5: carbamoyl-phosphate synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.6: asparaginyl-tRNA synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.7: glutaminyl-tRNA synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.8: Now EC 2.6.1.85
  


• 
  EC 6.3.5.9: hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.10: adenosylcobyric acid synthase (glutamine-hydrolysing)
  


• 
  EC 6.3.5.11: cobyrinate a,c-diamide synthase
  

EC 6.4: Forming Carbon-Carbon Bonds[edit]

• 
  EC 6.4.1.1: pyruvate carboxylase
  


• 
  EC 6.4.1.2: acetyl-CoA carboxylase
  


• 
  EC 6.4.1.3: propionyl-CoA carboxylase
  


• 
  EC 6.4.1.4: methylcrotonoyl-CoA carboxylase
  


• 
  EC 6.4.1.5: geranoyl-CoA carboxylase
  


• 
  EC 6.4.1.6: acetone carboxylase
  


• 
  EC 6.4.1.7: 2-oxoglutarate carboxylase
  


• 
  EC 6.4.1.8: acetophenone carboxylase
  

EC 6.5: Forming Phosphoric Ester Bonds[edit]

• 
  EC 6.5.1.1: DNA ligase (ATP)
  


• 
  EC 6.5.1.2: DNA ligase (NAD+)
  


• 
  EC 6.5.1.3: RNA ligase (ATP)
  


• 
  EC 6.5.1.4: RNA-3'-phosphate cyclase
  

EC 6.6: Forming Nitrogen-Metal Bonds[edit]

EC 6.6.1: Forming Coordination Complexes[edit]

• 
  EC 6.6.1.1: magnesium chelatase
  


• 
  EC 6.6.1.2: cobaltochelatase