title: In vitro deacylation of lipopolysaccharide of Salmonella minnesota by Acanthamoeba castellanii enzymes.
abstract: Enzymatic deacylation of the lipopolysaccharide isolated from a Salmonella Rd mutant by a cell-free preparation from Acanthamoeba castellanii has been studied. The degradation was found to be dependent on the presence of a surface-active component (Triton X-100) in the reaction mixture. The lipid A part of the lipopolysaccharide was the primary target of the enzymes, which cleaved with high efficiency the ester-bound long-chain nonhydroxylated and 3-hydroxylated acyl residues, i.e. lauric, myristic, palmitic and 3-hydroxymyristic acid. The cell-free preparation also exhibited amidase activity cleaving about 50% of the amide-bound 3-hydroxymyristic acid residues. In addition the extract proved to possess phosphatase activity liberating ester-bound and glycosidically bound phosphate groups of lipid A. On the other hand, the glucosaminyl-beta 1,6-glucosamine disaccharide was not degraded and remained bound to the oligosaccharide part (heptose/3-deoxyoctulosonic acid) of the lipopolysaccharide.
mesh_terms: D000581:Amidohydrolases / Q000032:analysis; D000656:Amoeba / Q000201:enzymology*; D003902:Detergents / Q000494:pharmacology; D004950:Esterases / Q000032:analysis; D005227:Fatty Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008070:Lipopolysaccharides / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis; D012475:Salmonella
chemical_list: D003902:Detergents; D005227:Fatty Acids; D008070:Lipopolysaccharides; D004950:Esterases; D010744:Phosphoric Monoester Hydrolases; D000581:Amidohydrolases; C019665:amidase