IUBMB Enzyme Nomenclature


Accepted name: L-threonine—[L-threonyl-carrier protein] ligase

Reaction: ATP + L-threonine + holo-[L-threonyl-carrier protein] = AMP + diphosphate + L-threonyl-[L-threonyl-carrier protein] (overall reaction)
(1a) ATP + L-threonine = diphosphate + (L-threonyl)adenylate
(1b) (L-threonyl)adenylate + holo-[L-threonyl-carrier protein] = AMP + L-threonyl-[L-threonyl-carrier protein]

Other name(s): dhbF (gene name); pmsD (gene name); syrB1 (gene name)

Systematic name: L-threonine:[L-threonyl-carrier protein] ligase (AMP-forming)

Comments: The adenylation domain of the enzyme catalyses the activation of L-threonine to (L-threonyl)adenylate, followed by the transfer of the activated compound to the free thiol of a phosphopantetheine arm of a peptidyl-carrier protein domain. The peptidyl-carrier protein domain may be part of the same protein (as in the case of DhbF in bacillibactin biosynthesis), or of a different protein (as in the case of PmsD in pseudomonine biosynthesis). This activity is often found as part of a larger non-ribosomal peptide synthase.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Vaillancourt, F.H., Yin, J. and Walsh, C.T. SyrB2 in syringomycin E biosynthesis is a nonheme FeII α-ketoglutarate- and O2-dependent halogenase. Proc. Natl. Acad. Sci. USA 102 (2005) 10111-10116. [PMID: 16002467]

2. Sattely, E.S. and Walsh, C.T. A latent oxazoline electrophile for N-O-C bond formation in pseudomonine biosynthesis. J. Am. Chem. Soc. 130 (2008) 12282-12284. [PMID: 18710233]

[EC created 2021]

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