The Mitochondrial Intermembrane Loop Region of Rat Carnitine Palmitoyltransferase 1A Is a Major Determinant of Its Malonyl-CoA Sensitivity
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منابع مشابه
Interacting 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...
متن کاملEffects of pH on the interaction of substrates and malonyl-CoA with mitochondrial carnitine palmitoyltransferase I.
The kinetics of carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) were examined in mitochondria from rat liver, heart and skeletal muscle as a function of pH over the range 6.8-7.6. In all three tissues raising the pH resulted in a fall in the Km for carnitine, no change in the Km for palmitoyl-CoA or Octanoyl-CoA, and a marked decrease in the inhibitory potency of malonyl-CoA. Studies with...
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 کاملSigmoid kinetics of purified beef heart mitochondrial carnitine palmitoyltransferase. Effect of pH and malonyl-CoA.
The kinetics of purified beef heart mitochondrial carnitine palmitoyltransferase have been extensively investigated with a semiautomated system and the computer program TANKIN and shown to be sigmoidal with both acyl-CoA and L-carnitine. In contrast, Michaelis-Menten kinetics were found with carnitine octanoyltransferase. The catalytic activity of carnitine palmitoyltransferase is strongly pH d...
متن کاملAltered sensitivity of carnitine palmitoyltransferase to inhibition by malonyl-CoA in ketotic diabetic rats.
Carnitine palmitoyltransferase of liver mitochondria prepared from ketotic diabetic rats has a diminished sensitivity to inhibition by malonyl-CoA compared with carnitine palmitoyltransferase of mitochondria prepared from normal fed rats.
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2006
ISSN: 0021-9258
DOI: 10.1074/jbc.m600843200