IUBMB Enzyme Nomenclature


Accepted name: lipid-A-disaccharide synthase

Reaction: a UDP-2-N,3-O-bis[(3R)-3-hydroxyacyl]-α-D-glucosamine + a lipid X = UDP + a lipid A disaccharide

For diagram of lreaction click here

Glossary: a lipid X = 2-N-[(3R)-3-hydroxyacyl]-3-O-[(3R)-3-hydroxyacyl]-α-D-glucosamine 1-phosphate =
a lipid A disaccharide = a 2-deoxy-2-{[(3R)-3-hydroxyacyl]amino}-3-O-[(3R)-3-hydroxyacyl]-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxyacyl]-2-{[(3R)-3-hydroxyacyl]amino}-1-O-phospho-α-D-glucopyranose

Other name(s): lpxB (gene name); UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine:2,3-bis-(3-hydroxytetradecanoyl)-β-D-glucosaminyl-1-phosphate 2,3-bis(3-hydroxytetradecanoyl)-glucosaminyltransferase (incorrect)

Systematic name: UDP-2-N,3-O-bis[(3R)-3-hydroxyacyl]-α-D-glucosamine:2-N,3-O-bis[(3R)-3-hydroxyacyl]-α-D-glucosamine 1-phosphate 2-N,3-O-bis[(3R)-3-hydroxyacyl]-α-D-glucosaminyltransferase

Comments: Involved with EC (acyl-[acyl-carrier-protein]—UDP-N-acetylglucosamine O-acyltransferase) and EC (tetraacyldisaccharide 4'-kinase) in the biosynthesis of the phosphorylated glycolipid, lipid A, in the outer membrane of Gram-negative bacteria.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 105843-81-0


1. Ray, B.L., Painter, G. and Raetz, C.R.H. The biosynthesis of gram-negative endotoxin. Formation of lipid A disaccharides from monosaccharide precursors in extracts of Escherichia coli. J. Biol. Chem. 259 (1984) 4852-4859. [PMID: 6370995]

2. Crowell, D.N., Reznikoff, W.S. and Raetz, C.R.H. Nucleotide sequence of the Escherichia coli gene for lipid A disaccharide synthase. J. Bacteriol. 169 (1987) 5727-5734. [PMID: 2824445]

3. Metzger, L.E., 4th and Raetz, C.R. Purification and characterization of the lipid A disaccharide synthase (LpxB) from Escherichia coli, a peripheral membrane protein. Biochemistry 48 (2009) 11559-11571. [PMID: 19883124]

4. Bohl, T.E., Shi, K., Lee, J.K. and Aihara, H. Crystal structure of lipid A disaccharide synthase LpxB from Escherichia coli. Nat. Commun. 9 (2018) 377. [PMID: 29371662]

[EC created 1990, modified 2021]

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