acyloxyacyl hydrolase
{{Short description|Protein family}}
{{infobox enzyme
| Name = acyloxyacyl hydrolase
| EC_number = 3.1.1.77
| CAS_number =
| GO_code = 0050528
| image = 5w78.jpg
| width = 270
| caption = Acyloxyacyl hydrolase heterodimer, Human
}}
The enzyme acyloxyacyl hydrolase (EC 3.1.1.77, AOAH) was discovered because it catalyzes the reaction
:3-(acyloxy)acyl group of bacterial toxin + H2O = 3-hydroxyacyl group of bacterial toxin + a fatty acid
The enzyme removes from lipid A the secondary acyl chains that are needed for lipopolysaccharides to be recognized by the MD-2--TLR4 receptor on animal cells. This reaction inactivates the lipopolysaccharide (endotoxin); the tetraacyl lipid A product can inhibit LPS signaling.
Acyloxyacyl hydrolase is produced by monocyte-macrophages, neutrophils, dendritic cells, NK cells, ILC1 cells, and renal cortical tubule cells. It is a protein of about 60 kDa that has two disulfide-linked subunits. The smaller subunit, of about 14 kDa (including glycosylation), is a member of the SAPLIP (saposin-like protein) family along with amoebapore, granulysin, acid sphingomyelinase, surfactant protein B, and the 4 sphingolipid activator proteins (saposins). The larger subunit, of 50 kDa, contains the active site serine and the other elements of the His-Asp-Ser triad; AOAH is a GDSL lipase that has activity toward certain glycerolipids in addition to its presumed major in vivo substrate, LPS.
Also see "AOAH".
References
{{reflist|1}}
- {{cite journal | vauthors = Erwin AL, Munford RS | year = 1990 | title = Deacylation of structurally diverse lipopolysaccharides by human acyloxyacyl hydrolase | journal = J. Biol. Chem. | volume = 265 | pages = 16444–9 | pmid = 2398058 | issue = 27 }}
- {{cite journal |author1 = Hagen, F. |author2 =O'Hara PJ, Munford RS | year = 1991 | title = Expression |author3 =characterization of recombinant human acyloxyacyl hydrolase, a leukocyte enzyme that deacylates bacterial lipopolysaccharides | journal = Biochemistry | volume = 30 | pages = 8415–8423 | pmid = 1883828 | doi = 10.1021/bi00098a020 | issue = 34 }}
- {{cite journal | vauthors = Munford RS, Hunter JP | year = 1992 | title = Acyloxyacyl hydrolase, a leukocyte enzyme that deacylates bacterial lipopolysaccharides, has phospholipase, lysophospholipase, diacylglycerollipase, and acyltransferase activities in vitro | journal = J. Biol. Chem. | volume = 267 | pages = 10116–21 | pmid = 1577781 | issue = 14 }}
- {{cite journal | vauthors = Akoh CC, Lee GC, Shaw JF | year = 2004 | title = GDSL family of serine esterases/lipases | journal = Prog. Lipid Res. | volume = 43 | pages= 534–552 | pmid = 15522763 | doi=10.1016/j.plipres.2004.09.002}}
- {{cite journal |vauthors=Munford RS, Weiss JP, Lu M |title= Biochemical transformation of bacterial lipopolysaccharides by acyloxyacyl hydrolase reduces host injury and promotes recovery | journal = J Biol Chem |volume= 295 |year= 2020 |issue= 51 |pages= 17842-1785 |PMID= 33454018 |doi= 10.1074/jbc.REV120.015254|doi-access= free |pmc= 7762960 }}
{{Esterases}}
{{Enzymes}}
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Category:Enzymes of unknown structure
{{3.1-enzyme-stub}}