“Acyloxyacyl hydrolase”的意思、由来-开放百科全书

词条

Acyloxyacyl hydrolase

释义

References

{{enzyme
| Name = acyloxyacyl hydrolase
| EC_number = 3.1.1.77
| CAS_number =
| IUBMB_EC_number = 3/1/1/77
| GO_code = 0050528
| image = 5w78.jpg
| width = 270
| caption = Acyloxyacyl hydrolase heterodimer, Human
}}

In enzymology, an acyloxyacyl hydrolase ({{EC number|3.1.1.77}}) is an enzyme that catalyzes the chemical reaction

3-(acyloxy)acyl group of bacterial lipopolysaccharide (lipid A moiety) 3-hydroxyacyl group of bacterial lipopolysaccharide + a fatty acid

Hence, this enzyme has one substrate, the 3-(acyloxy)acyl groups of bacterial lipopolysaccharides, and two products, [partially deacylated lipopolysaccharide] and 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). Acyloxyacyl hydrolase is produced by monocyte-macrophages, neutrophils, dendritic cells, and renal cortical epithelial cells. It is a protein of Mr = ~60,000 that has two disulfide-linked subunits. The smaller subunit, of Mr = ~14,000 (including glycosylation), is a member of the SAPLIP (saposin-like protein) family along with amoebopore, granulysin, acid sphingomyelinase, surfactant protein B, and the 4 sphingolipid activator proteins (saposins). The larger subunit, Mr = 50,000, 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.

References

{{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}}

2 : EC 3.1.1|Enzymes of unknown structure

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