Abstract: | Two fatty acyl amidases have been partially purified from the slime mold, Dictyostelium discoideum. Their action on lipopolysaccharide derivatives, especially Compound I, has been studied. Amidase I removes specifically the beta-hydroxymyristyl group, which is present on the amino group adjacent to the C-1 phosphate. The product, Compound V, is then a substrate for Amidase II, which removes the remaining beta-hydroxymyristyl group from the amino group in the distal glucosamine ring to give Compound VI. Compound I itself is resistant to Amidase II. Thus, the two enzymes show a high degree of structural specificity. The structure of lipopolysaccharide from the E. coli K-12 mutant is concluded in the light of studies reported in this and the accompanying papers, and this structure is discussed in relation to other bacterial lipopolysaccharides. |