IUBMB Enzyme Nomenclature


Accepted name: lipopolysaccharide heptosyltransferase I

Reaction: ADP-L-glycero-β-D-manno-heptose + an α-Kdo-(2→4)-α-Kdo-(2→6)-[lipid A] = ADP + an α-Hep-(1→5)-[α-Kdo-(2→4)]-α-Kdo-(2→6)-[lipid A]

Glossary: Lipid A is a lipid component of the lipopolysaccharides (LPS) of Gram-negative bacteria. It consists of two glucosamine units connected by a β(1→6) bond and decorated with four to seven acyl chains and up to two phosphate groups.
Hep = L-glycero-D-manno-heptose

Other name(s): HepI; rfaC (gene name); WaaC; heptosyltransferase I (ambiguous)

Systematic name: ADP-L-glycero-β-D-manno-heptose:an α-Kdo-(2→4)-α-Kdo-(2→6)-[lipid A] 5-α-heptosyltransferase

Comments: The enzyme catalyses a glycosylation step in the biosynthesis of the inner core oligosaccharide of the lipopolysaccharide (endotoxin) of many Gram-negative bacteria.

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


1. Kadrmas, J.L. and Raetz, C.R. Enzymatic synthesis of lipopolysaccharide in Escherichia coli. Purification and properties of heptosyltransferase i. J. Biol. Chem. 273 (1998) 2799-2807. [PMID: 9446588]

2. de Kievit, T.R. and Lam, J.S. Isolation and characterization of two genes, waaC (rfaC) and waaF (rfaF), involved in Pseudomonas aeruginosa serotype O5 inner-core biosynthesis. J. Bacteriol. 179 (1997) 3451-3457. [PMID: 9171387]

3. Klena, J.D., Gray, S.A. and Konkel, M.E. Cloning, sequencing, and characterization of the lipopolysaccharide biosynthetic enzyme heptosyltransferase I gene (waaC) from Campylobacter jejuni and Campylobacter coli. Gene 222 (1998) 177-185. [PMID: 9831648]

4. Gronow, S., Oertelt, C., Ervela, E., Zamyatina, A., Kosma, P., Skurnik, M. and Holst, O. Characterization of the physiological substrate for lipopolysaccharide heptosyltransferases I and II. J Endotoxin Res 7 (2001) 263-270. [PMID: 11717579]

5. Grizot, S., Salem, M., Vongsouthi, V., Durand, L., Moreau, F., Dohi, H., Vincent, S., Escaich, S. and Ducruix, A. Structure of the Escherichia coli heptosyltransferase WaaC: binary complexes with ADP and ADP-2-deoxy-2-fluoro heptose. J. Mol. Biol. 363 (2006) 383-394. [PMID: 16963083]

[EC created 2022]

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