The enzyme catalyses a step of lipid A biosynthesis. LpxD from Escherichia coli prefers (R,S)-3-hydroxytetradecanoyl-[acyl-carrier protein] over (R,S)-3-hydroxyhexadecanoyl-[acyl-carrier protein] [1]. E. 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].
