IUBMB Enzyme Nomenclature


Accepted name: UDP-3-O-(3-hydroxymyristoyl)glucosamine N-acyltransferase

Reaction: (3R)-3-hydroxytetradecanoyl-[acyl-carrier protein] + UDP-3-O-[(3R)-3-hydroxytetradecanoyl]-α-D-glucosamine = UDP-2,3-bis[O-(3R)-3-hydroxytetradecanoyl]-α-D-glucosamine + a holo-[acyl-carrier protein]

For diagram of reaction click here.

Glossary: myristoyl = tetradecanoyl

Other name(s): UDP-3-O-acyl-glucosamine N-acyltransferase; UDP-3-O-(R-3-hydroxymyristoyl)-glucosamine N-acyltransferase; acyltransferase LpxD; acyl-ACP:UDP-3-O-(3-hydroxyacyl)-GlcN N-acyltransferase; firA (gene name); lpxD (gene name)

Systematic name: (3R)-3-hydroxymyristoyl-[acyl-carrier protein]:UDP-3-O-[(3R)-3-hydroxymyristoyl]-α-D-glucosamine N-acetyltransferase

Comments: The enzyme catalyses a step of lipid A biosynthesis. LpxD from Escherichia prefers (R,S)-3-hydroxymyristoyl-[acyl-carrier protein] over (R,S)-3-hydroxypalmitoyl-[acyl-carrier protein] [1]. Escherichia coli lipid A acyltransferases do not have an absolute specificity for 14-carbon hydroxy fatty acids but can transfer fatty acids differing by one carbon unit if the fatty acid substrates are available. When grown on 1% propionic acid, lipid A also contains the odd-chain fatty acids tridecanoic acid, pentadecanoic acid, hydroxytridecanoic acid, and hydroxypentadecanoic acid [5].

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


1. Bartling, C.M. and Raetz, C.R. Crystal structure and acyl chain selectivity of Escherichia coli LpxD, the N-acyltransferase of lipid A biosynthesis. Biochemistry 48 (2009) 8672-8683. [PMID: 19655786]

2. Buetow, L., Smith, T.K., Dawson, A., Fyffe, S. and Hunter, W.N. Structure and reactivity of LpxD, the N-acyltransferase of lipid A biosynthesis. Proc. Natl. Acad. Sci. USA 104 (2007) 4321-4326. [PMID: 17360522]

3. Bartling, C.M. and Raetz, C.R. Steady-state kinetics and mechanism of LpxD, the N-acyltransferase of lipid A biosynthesis. Biochemistry 47 (2008) 5290-5302. [PMID: 18422345]

4. Kelly, T.M., Stachula, S.A., Raetz, C.R. and Anderson, M.S. The firA gene of Escherichia coli encodes UDP-3-O-(R-3-hydroxymyristoyl)-glucosamine N-acyltransferase. The third step of endotoxin biosynthesis. J. Biol. Chem. 268 (1993) 19866-19874. [PMID: 8366125]

5. Bainbridge, B.W., Karimi-Naser, L., Reife, R., Blethen, F., Ernst, R.K. and Darveau, R.P. Acyl chain specificity of the acyltransferases LpxA and LpxD and substrate availability contribute to lipid A fatty acid heterogeneity in Porphyromonas gingivalis. J. Bacteriol. 190 (2008) 4549-4558. [PMID: 18456814]

[EC created 2010]

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