EC - Acyloxyacyl hydrolase

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IntEnz Enzyme Nomenclature


Accepted name:
acyloxyacyl hydrolase
Systematic name:



The substrate is lipid A on the reducing end of the toxic lipopolysaccharide (LPS) of Salmonella typhimurium and related organisms. It consists of diglucosamine, β-D-GlcN-(1→6)-D-GlcN, attached by glycosylation on O-6 of its non-reducing residue, phosphorylated on O-4 of this residue and on O-1 of its potentially reducing residue. Both residues carry 3-(acyloxy)acyl groups on N-2 and O-3. The enzyme from human leucocytes detoxifies the lipid by hydrolysing the secondary acyl groups from O-3 of the 3-hydroxyacyl groups on the disaccharide (LPS). It also possesses a wide range of phospholipase and acyltransferase activities [e.g. EC (phospholipase A2), EC (lysophospholipase), EC (phospholipase A1) and EC (phosphatidylinositol deacylase)], hydrolysing diacylglycerol and phosphatidyl compounds, but not triacylglycerols. It has a preference for saturated C12-C16 acyl groups.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050528


  1. Erwin, A.L. and Munford, R.S.
    Deacylation of structurally diverse lipopolysaccharides by human acyloxyacyl hydrolase.
    J. Biol. Chem. 265: 16444-16449 (1990). [PMID: 2398058]
  2. Hagen, F.S., Grant, F.J., Kuijper, J.L., Slaughter, C.A., Moomaw, C.R., Orth, K., OʼHara, P.J. and Munford, R.S.
    Expression and characterization of recombinant human acyloxyacyl hydrolase, a leukocyte enzyme that deacylates bacterial lipopolysaccharides.
    Biochemistry 30: 8415-8423 (1991). [PMID: 1883828]
  3. Munford, R.S. and Hunter, J.P.
    Acyloxyacyl hydrolase, a leukocyte enzyme that deacylates bacterial lipopolysaccharides, has phospholipase, lysophospholipase, diacylglycerollipase, and acyltransferase activities in vitro.
    J. Biol. Chem. 267: 10116-10121 (1992). [PMID: 1577781]

[EC created 2001]