Fatty acyl amidases from Dictyostelium discoideum that act on lipopolysaccharide and derivatives. I. Partial purification and properties.
Two amidases have been partially purified from the slime mold Dictyostelium discoideum; these act sequentially on the beta-hydroxymyristyl-amide groups present in the lipopolysaccharide derivative (4'-O-phosphoryl-N-beta-hydroxymyristyl-D-glucosaminyl)-beta-(1 leads to 6)-N-beta-hydroxymyristyl-D-glucosamine-1-phosphate (III). Amidase-I, which specifically removes the myristyl chain near the 1-phosphate of compound III (apparent Km, 3.7 microM), has been purified 110-fold from a lysate of D. discoideum NC4 cultivated on Escherichia coli. The partially purified enzyme contains no other amidase or phosphatase activities; however, an esterase activity can be detected. The second amidase has been purified about 12-fold from the extracellular fluid of D. discoideum AX3 cultured axenically. This amidase hydrolyzes the distal amide linkage in III (apparent Km, approximately 20 microM) only after prior deacylation of the first site by amidase-I. The preparation is free from phosphatases and glycosidases that can act on lipopolysaccharide. The differential expression of the amidases in D. discoideum and some of their kinetic properties have been described. The amidases should prove useful in structure-function studies of lipopolysaccharide.
D000581:Amidohydrolases / Q000302:isolation & purification / Q000378:metabolism*; D004023:Dictyostelium / Q000201:enzymology*; D007700:Kinetics; D008070:Lipopolysaccharides; D013379:Substrate Specificity
D008070:Lipopolysaccharides; D000581:Amidohydrolases; C035588:fatty acyl amidases