Malonyl-CoA inhibition of peroxisomal carnitine octanoyltransferase
نویسندگان
چکیده
منابع مشابه
Malonyl-CoA inhibition of peroxisomal carnitine octanoyltransferase.
Although the malonyl-CoA sensitivity of peroxisomal carnitine octanoyltransferase (COT) is reportedly lost on solubilization, we show that malonyl-CoA does inhibit the purified enzyme. Assay conditions such as buffer composition, pH, acyl-CoA substrate and the presence or absence of BSA can affect the observed inhibition. When assayed in the absence of BSA, COT shows simple competitive inhibiti...
متن کاملEffects of fasting and malonyl CoA on the kinetics of carnitine palmitoyltransferase and carnitine octanoyltransferase in intact rat liver mitochondria.
There has been considerable interest in the observation that the overt form of carnitine palmitoyltransferase (CPT1) in liver mitochondria is potently inhibited by malonyl CoA [I ,2]. It has been suggested [2] that this is a competitive type of inhibition against long chain acyl CoA substrates. However, this is based upon measurements of ketogenesis [3-51 or indirect calculations of CPT, activi...
متن کاملMicrosomal malonyl-CoA-sensitive carnitine acyltransferase.
Liver microsomes contain two carnitine acyltransferase activities. One of these has properties closely corresponding to those of 88 kDa mitochondrial carnitine palmitoyltransferase-1 (CPT-1). Antisera against CPT-1 cross-react with an 88 kDa microsomal protein, suggesting that CPT-1 may be targeted to both microsomal and mitochondrial membranes. However, no experiments using cDNAs corresponding...
متن کاملIdentification of conserved amino acid residues in rat liver carnitine palmitoyltransferase I critical for malonyl-CoA inhibition. Mutation of methionine 593 abolishes malonyl-CoA inhibition.
Carnitine palmitoyltransferase (CPT) I, which catalyzes the conversion of palmitoyl-CoA to palmitoylcarnitine facilitating its transport through the mitochondrial membranes, is inhibited by malonyl-CoA. By using the SequenceSpace algorithm program to identify amino acids that participate in malonyl-CoA inhibition in all carnitine acyltransferases, we found 5 conserved amino acids (Thr(314), Asn...
متن کاملEffect of pH on malonyl-CoA inhibition of carnitine palmitoyltransferase I.
Malonyl-CoA inhibition of carnitine palmitoyltransferase I was found to be very pH-dependent. Malonyl-CoA concentrations causing 50% inhibition (I50) at pH 6.0, 6.5, 7.0, 7.5 and 8.0 were 0.04, 1, 9, 40 and 200 microM respectively. It is suggested that a lowering of intracellular pH, such as might occur in ketoacidosis, may attenuate hepatic fatty acid oxidation by increasing malonyl-CoA sensit...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1992
ISSN: 0264-6021,1470-8728
DOI: 10.1042/bj2860637