Galactoside acetyltransferase

Galactoside acetyltransferase (also known as Galactoside O-acetyltransferase, thiogalactoside transacetylase, β-galactoside transacetylase and GAT) is an enzyme that transfers an acetyl group from acetyl-CoA to β-galactosides, glucosides and lactosides. It is coded for by the lacA gene of the lac operon in E. coli.

Reaction

It catalyzes the following reaction:

acetyl-CoA + beta-D-galactoside → CoA + 6-acetyl-beta-D-galactoside

The kinetics of the enzyme were delineated in 1995.

Biological role

The enzyme's role in the classical E.coli lac operon remains unclear. However, the enzyme's cellular role may be to detoxify non-metabolizable pyranosides by acetylating them and preventing their reentry into the cell.

References

^ Wang XG, Olsen LR, Roderick SL (April 2002). "Structure of the lac operon galactoside acetyltransferase". Structure. 10 (4): 581–8. doi:10.1016/S0969-2126(02)00741-4. PMID 11937062.
Lewendon A, Ellis J, Shaw WV (November 1995). "Structural and mechanistic studies of galactoside acetyltransferase, the Escherichia coli LacA gene product". The Journal of Biological Chemistry. 270 (44): 26326–31. doi:10.1074/jbc.270.44.26326. PMID 7592843.
Roderick SL (June 2005). "The lac operon galactoside acetyltransferase". Comptes Rendus Biologies. 328 (6): 568–75. doi:10.1016/j.crvi.2005.03.005. PMID 15950163.
"Thiogalactoside transacetylase of the lactose operon as an enzyme for detoxification". 1976. {{cite journal}}: Cite journal requires |journal= (help)

External links

Media related to Galactoside acetyltransferase at Wikimedia Commons
galactoside+acetyltransferase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
EC 2.3.1.18

v t e Transferases: acyltransferases (EC 2.3)
2.3.1: other than amino-acyl groups	acetyltransferases: Acetyl-Coenzyme A acetyltransferase N-Acetylglutamate synthase Choline acetyltransferase Dihydrolipoyl transacetylase Acetyl-CoA C-acyltransferase Beta-galactoside transacetylase Chloramphenicol acetyltransferase N-acetyltransferase Serotonin N-acetyl transferase HGSNAT ARD1A Histone acetyltransferase P300/CBP NAT2 palmitoyltransferases: Carnitine O-palmitoyltransferase CPT1 CPT2 Serine C-palmitoyltransferase SPTLC1 SPTLC2 other: Acyltransferase like 2 Aminolevulinic acid synthase Beta-ketoacyl-ACP synthase Glyceronephosphate O-acyltransferase Lecithin—cholesterol acyltransferase Glycerol-3-phosphate O-acyltransferase 1-acylglycerol-3-phosphate O-acyltransferase 2-acylglycerol-3-phosphate O-acyltransferase ABHD5
2.3.2: Aminoacyltransferases	Gamma-glutamyl transpeptidase Peptidyl transferase Transglutaminase Tissue transglutaminase Keratinocyte transglutaminase Factor XIII
2.3.3: converted into alkyl on transfer	Citrate synthase Decylcitrate synthase Citrate (Re)-synthase Decylhomocitrate synthase 2-methylcitrate synthase 2-ethylmalate synthase 3-ethylmalate synthase ATP citrate lyase Malate synthase HMG-CoA synthase HMGCS2 2-hydroxyglutarate synthase 3-propylmalate synthase 2-isopropylmalate synthase Homocitrate synthase Sulfoacetaldehyde acetyltransferase

Transferases: acyltransferases (EC 2.3)

2.3.1: other than amino-acyl groups

2.3.2: Aminoacyltransferases

2.3.3: converted into alkyl on transfer

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)

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Reaction

Biological role

See also

References

External links