ENZYME

ENZYME entry: EC 3.1.1.77

Accepted Name

Acyloxyacyl hydrolase.

Reaction catalysed

3-(acyloxy)acyl group of bacterial toxin <=> 3-hydroxyacyl group of bacterial toxin + a fatty acid

Comment(s)

The substrate is lipid A on the reducing end of the toxic lipopolysaccharide (LPS) of Salmonella typhimurium and related organisms.
It consists of diglucosamine, beta-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 leukocytes detoxifies the lipid by hydrolyzing 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 3.1.1.4, EC 3.1.1.5, EC 3.1.1.32 and EC 3.1.1.52), hydrolyzing diacylglycerol and phosphatidyl compounds, but not triacylglycerols.
It has a preference for saturated C(12)-C(16) acyl groups.

Cross-references

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature

IUBMB Enzyme Nomenclature