Structural Model of a Malonyl-CoA-binding Site of Carnitine Octanoyltransferase and Carnitine Palmitoyltransferase I
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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 کاملStructural Model of the Catalytic Core of Carnitine Palmitoyltransferase I and Carnitine Octanoyltransferase (COT)
Carnitine palmitoyltransferase I (CPT I) and carnitine octanoyltransferase (COT) catalyze the conversion of longand medium-chain acyl-CoA to acylcarnitines in the presence of carnitine. We propose a common threedimensional structural model for the catalytic domain of both, based on fold identification for 200 amino acids surrounding the active site through a threading approach. The model is bas...
متن کاملMalonyl-CoA and carnitine palmitoyltransferase I: an expanding partnership.
Inhibition of mitochondrial carnitine palmitoyltransferase I (CPT I) by malonyl-CoA, the product of the acetyl-CoA carboxylase reaction, was first recognized in 1977 during the course of studies on hepatic ketogenesis and its regulation [ l ] . What emerged from that work was that with carbohydrate feeding (high insulin/low glucagon) the liver is actively engaged in fatty acid biosynthesis, the...
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 کاملInteracting effects of L-carnitine and malonyl-CoA on rat liver carnitine palmitoyltransferase.
Malonyl-CoA significantly increased the Km for L-carnitine of overt carnitine palmitoyltransferase in liver mitochondria from fed rats. This effect was observed when the molar palmitoyl-CoA/albumin concentration ratio was low (0.125-1.0), but not when it was higher (2.0). In the absence of malonyl-CoA, the Km for L-carnitine increased with increasing palmitoyl-CoA/albumin ratios. Malonyl-CoA di...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2002
ISSN: 0021-9258
DOI: 10.1074/jbc.m111628200