2-Bromopalmitoyl-CoA and 2-bromopalmitate: promiscuous inhibitors of membrane-bound enzymes.
Biochim Biophys Acta
; 1125(2): 203-9, 1992 Apr 23.
Article
em En
| MEDLINE
| ID: mdl-1571364
ABSTRACT
2-Bromopalmitate and 2-bromopalmitoyl-CoA have been shown to inhibit a variety of enzymes and proteins associated with lipid metabolism. We found that both of the brominated compounds were non-competitive inhibitors of two microsomal activities of triacylglycerol biosynthesis, the mono- and diacylglycerol acyltransferases. With both compounds, the calculated Ki values were lower than the Km value for the palmitoyl-CoA substrate. In addition to inhibiting two other lipid synthetic activities, fatty acid CoA ligase and glycerol-3-P acyltransferase, 2-bromopalmitate and 2-bromopalmitoyl-CoA also inhibited two microsomal enzyme activities that are not related to lipid metabolism, NADPH cytochrome-c reductase and glucose-6-phosphatase. Inhibition of the three acyltransferases and fatty acid CoA ligase could be overcome by the addition of phospholipid vesicles, and 2-bromo[14C]palmitate readily labeled a large number of membrane-bound proteins as well as cytosolic proteins that had been solubilized in SDS. Thus, it appears likely that the inhibitory properties of the brominated compounds strongly depend on the effective concentration of the inhibitor within membranes rather than on any specific affinity for an acyl-chain binding region of the enzyme.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Palmitatos
/
Palmitoil Coenzima A
/
Membranas Intracelulares
/
Proteínas de Membrana
Limite:
Animals
Idioma:
En
Ano de publicação:
1992
Tipo de documento:
Article