Acyl-CoA

About: Acyl-CoA is a research topic. Over the lifetime, 527 publications have been published within this topic receiving 25134 citations. The topic is also known as: Acyl Coenzyme A.

Antarctic fish tissues preferentially catabolize monoenoic fatty acids

Abstract: Tissues of Antarctic marine fishes are very high in lipids, predominantly triacylglycerols (TAG). In addition to conferring static lift to these swimbladderless fishes, these rich lipid stores long have been considered as an important caloric resource to the animals. We have performed in vitro measurements of the rates of oxidation of 14C-labeled carbohydrates and fatty acids by oxidative skeletal muscle and heart ventricle of an Antarctic teleost, Gobionotothen gibberifrons to assess the relative importance of these substrates to aerobic energy metabolism. Capacities for regeneration of ATP calculated from oxidation rates of these fuels clearly indicate that fatty acids are more effective substrates of energy metabolism than either glucose or lactate with both tissues. Substrate competition experiments conducted between the saturated fatty acid palmitate (16:0) and the monoenoic unsaturate oleate (18:1) comparing the oxidation rate of radiolabeled fatty acid in the presence and absence of unlabeled competitor demonstrate a clear preference of both tissue types for catabolism of the monounsaturated substrate. Measurements of maximal activity of the putative flux-generating enzyme of mitochondrial β-oxidation, carnitine palmitoyltransferase (CPT), with a variety of fatty acyl CoA esters also show significant preference for a monoenoic fatty acyl CoA, palmitoleoyl CoA (16:1). The general pattern of results suggests that monounsaturated fatty compounds are the most readily utilized substrates for energy metabolism by oxidation muscle tissues of this Antarctic species. © 1995 Wiley-Liss, Inc.

Fat metabolism during exercise: a review. Part I: fatty acid mobilization and muscle metabolism.

Abstract: This is the first part in a series of three articles about fat metabolism during exercise. In this part the mobilization of fatty acids and their metabolism will be discussed as well as the possible limiting steps of fat oxidation. It is known for a long time that fatty acids are an important fuel for contracting muscle. After lipolysis, fatty acids from adipose tissue have to be transported through the blood to the muscle. Fatty acids derived from circulating TG may also be used as a fuel but are believed to be less important during exercise. In the muscle the IMTG stores may also provide fatty acids for oxidation after stimulation of hormone sensitive lipase. In the muscle cell, fatty acids will be transported by carrier proteins (FABP), and after activation, fatty acyl CoA have to cross the mitochondrial membrane through the carnitine palmytoyl transferase system, after which the acyl CoA will be degraded to acetyl CoA for oxidation. The two steps that are most likely to limit fat oxidation are fatty acid mobilization from adipose tissue and transport of fatty acids into the mitochondria along with mitochondrial density and the muscles capacity to oxidize fatty acids.

AtABCA9 transporter supplies fatty acids for lipid synthesis to the endoplasmic reticulum

Abstract: Fatty acids, the building blocks of biological lipids, are synthesized in plastids and then transported to the endoplasmic reticulum (ER) for assimilation into specific lipid classes. The mechanism of fatty acid transport from plastids to the ER has not been identified. Here we report that AtABCA9, an ABC transporter in Arabidopsis thaliana, mediates this transport. AtABCA9 was localized to the ER, and atabca9 null mutations reduced seed triacylglycerol (TAG) content by 35% compared with WT. Developing atabca9 seeds incorporated 35% less (14)C-oleoyl-CoA into TAG compared with WT seeds. Furthermore, overexpression of AtABCA9 enhanced TAG deposition by up to 40%. These data strongly support a role for AtABCA9 as a supplier of fatty acid substrates for TAG biosynthesis at the ER during the seed-filling stage. AtABCA9 may be a powerful tool for increasing lipid production in oilseeds.

Mammalian fatty acid elongases.

Abstract: Very long chain fatty acids confer functional diversity on cells by variations in their chain length and degree of unsaturation. Microsomal fatty acid elongation represents the major pathway for determining the chain length of saturated, monounsaturated, and polyunsaturated fatty acids in cellular lipids. The overall reaction for fatty acid elongation involves four enzymes and utilizes malonyl CoA, NADPH, and fatty acyl CoA as substrates. While the fundamental pathway and its requirements have been known for many years, recent advances have revealed a family of enzymes involved in the first step of the reaction, i.e., the condensation reaction. Seven fatty acid elongase subtypes (Elovl #1-7) have been identified in the mouse, rat, and human genomes. These enzymes determine the rate of overall fatty acid elongation. Moreover, these enzymes also display differential substrate specificity, tissue distribution, and regulation, making them important regulators of cellular lipid composition as well as specific cellular functions. Herein, methods are described to measure elongase activity, analyze elongation products, and alter cellular elongase expression.