In enzymology, a lipid-A-disaccharide synthase (EC 2.4.1.182) is an enzyme that catalyzes the chemical reaction

UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine + 2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate UDP + 2,3-bis(3-hydroxytetradecanoyl)-D-glucosaminyl-1,6-beta-D-2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate

Thus, the two substrates of this enzyme are UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine and 2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate, whereas its 2 products are UDP and 2,3-bis(3-hydroxytetradecanoyl)-D-glucosaminyl-1,6-beta-D-2,3-bis(3-hydroxytetradecanoyl)-beta-D-glucosaminyl 1-phosphate.

This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-2,3-bis(3-hydroxytetradecanoyl)glucosamine:2,3-bis(3-hydroxytet radecanoyl)-beta-D-glucosaminyl-1-phosphate 2,3-bis(3-hydroxytetradecanoyl)-glucosaminyltransferase. This enzyme participates in lipopolysaccharide biosynthesis.

• Crowell DN, Reznikoff WS, Raetz CR (1987). "Nucleotide sequence of the Escherichia coli gene for lipid A disaccharide synthase". J. Bacteriol. 169 (12): 5727–34. PMC 214086. PMID 2824445.
• Ray BL, Painter G, Raetz CR (1984). "The biosynthesis of gram-negative endotoxin. Formation of lipid A disaccharides from monosaccharide precursors in extracts of Escherichia coli". J. Biol. Chem. 259 (8): 4852–9. PMID 6370995.