EC 6 Ligases

Important Note: This version is formatted using the font symbol for Greek letters. If you cannot see a Delta (a triangle) in quotation marks next "δ" click here for a version where Greek letters are created using graphic images.



Recommended name: 4-chlorobenzoate-CoA ligase

Reaction: 4-chlorobenzoate + CoA + ATP = 4-chlorobenzoyl-CoA + AMP + diphosphate

Systematic name: 4-chlorobenzoate:CoA ligase

Comments: requires Mg2+. This enzyme is part of the bacterial 2,4-dichlorobenzoate degradation pathway.


1. Dunaway-Mariano, D., Babbitt, P.C. On the origins and functions of the enzymes of the 4-chlorobenzoate to 4-hydroxybenzoate converting pathway. Biodegradation 5 (1994) 259-276. [PMID: 7765837]

2. Loffler, F., Muller, R., Lingens, F. Purification and properties of 4-halobenzoate-coenzyme A ligase from Pseudomonas sp. CBS3. Biol. Chem. Hoppe-Seyler 373 (1992) 1001-1007. [PMID: 1418673]

3. Chang, K.H., Liang, P.H., Beck, W., Scholten, J.D., Dunaway-Mariano, D. Isolation and characterization of the three polypeptide components of 4-chlorobenzoate dehalogenase from Pseudomonas sp. strain CBS-3. Biochemistry 31 (1992) 5605-5610. [PMID: 1610806]


Recommended name: glutathionylspermidine synthase

Reaction: γ-L-glutamyl-L-cysteinyl-glycine + spermidine + ATP = N1-(γ-L-glutamyl-L-cysteinyl-glycyl)-spermidine + ADP + phosphate

(Glutathione + spermidine + ATP = glutathionylspermidine + ADP + phosphate)

Other name(s): glutathione:spermidine ligase (ADP-forming)

Systematic name: γ-L-Glutamyl-L-cysteinyl-glycine:spermidine ligase (ADP-forming) [spermidine is numbered so that atom N-1 is in the amino group of the aminopropyl part of the molecule]

Comments: Requires magnesium ions. Involved in the synthesis of trypanothione in trypanosomatids. The enzyme from E. coli is bifunctional and also catalyses the glutathionylspermidine amidase (EC reaction, resulting in a net hydrolysis of ATP.


1. Smith, K., Nadeau, K., Bradley, M., Walsh, C.T., Fairlamb, A.H. Purification of glutathionylspermidine and trypanothione synthase from Crithidia fasciculata. Protein Sci. 1 (1992) 874-883. [PMID: 1304372]

2. Bollinger, J.M., Kwon, D.S., Huisman, G.W., Kolter, R., Walsh, C.T. Glutathionylspermidine metabolism in E. coli. Purification, cloning, overproduction and characterization of a bifunctional glutathionyl spermidine synthetase/amidase. J. Biol. Chem. 270 (1995) 14031-14041. [PMID: 7775463]


Recommended name: trypanothione synthase

Reaction: γ-L-glutamyl-L-cysteinyl-glycine + N1-(γ-L-glutamyl-L-cysteinyl-glycyl)-spermidie + ATP = N1,N8-bis-(γ-L-glutamyl-L-csteinyl-glycyl)-spermidine + ADP + phosphate

(glutathione + glutathionylspermidine + ATP = N1,N8-bis-(glutathionyl)spermidine + ADP + phosphate)

Systematic name: glutathionylspermidine:glutathione ligase (ADP-forming)

Comments: involved in the synthesis of trypanothione in trypanosomatids


1. Smith, K., Nadeau, K., Bradley, M., Walsh, C.T., Fairlamb, A.H. Purification of glutathionyl spermidine and trypanothione synthase from Crithidia fasciculata. Protein Sci. 1 (1992) 874-883. [PMID: 1304372]


Recommended name: tubulin-tyrosine ligase

Reaction: ATP + detyrosinated α-tubulin + L-tyrosine = α-tubulin + ADP + phosphate

Systematic name: α-tubulin-L-tyrosine ligase (ADP-forming)

Comments: L-Tyrosine is linked via a peptide bond to the C-terminus of de-tyrosinated α-tubulin (des-Tyrω-α-tubulin). The enzyme is highly specific for α-tubulin and moderately specific for ATP and L-tyrosine. L-Phenylalanine and 3,4-dihydroxy-L-phenylalanine are transferred but with higher Km values.


1. Wehland, J., Schröder, H.C., Weber, K. Isolation and purification of tubulin-tyrosine ligase. Methods Enzymol. 134 (1986) 170-179. [PMID: 3821560]

2. Rudiger, M., Wehland, J., Weber, K. The carboxy-terminal peptide of detyrosinated alpha tubulin provides a minimal system to study the substrate specificity of tubulin-tyrosine ligase. Eur. J. Biochem. 220 (1994) 309-320. [PMID: 7510228]

Return to Supplement index