Ethanolamine phosphates, hydrophobic

Lipid A of Salmonella contains glucosamine, fatty acid and phosphate, with variable amounts of phosphoethanolamine and 4-amino-L-arabinose. Two molecules of glucosamine are pi,6-linked to each other and are very heavily substituted by fatty acyl residues. There are four molecules of 3-hydroxymyristate, seven molecules of long-chain fatty acid and three molecules of non-hydroxylated fatty acid per disaccharide, producing an extremely hydrophobic structure. The first glucosamine residue is attached to phosphate at C-1 and, thence, to ethanolamine and the second is substituted at C-4 by phosphate and, thence, can be attached to 4-amino-L-arabinose. For reviews of this structure see Westphal et al (1981) and Reitschel et al. (1981). It should be noted that lipid A is microheterogeneous. 

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