Fatty acid-binding protein

About: Fatty acid-binding protein is a research topic. Over the lifetime, 1721 publications have been published within this topic receiving 81530 citations. The topic is also known as: FABP.

Contribution of FAT/CD36 to the regulation of skeletal muscle fatty acid oxidation: an overview.

Abstract: Long chain fatty acids (LCFAs) are an important substrate for ATP production within the skeletal muscle The process of LCFA delivery from adipose tissue to muscle mitochondria involves many regulatory steps Recently, it has been recognized that LCFA oxidation is not only dependent on LCFA delivery to the muscle, but also on regulatory steps within the muscle Increasing selected fatty acid binding proteins/transporters on the plasma membrane facilitates a very rapid LCFA increase into the muscle, independent of any changes in LCFA delivery to the muscle Such a mechanism of LCFA transporter translocation is activated by muscle contraction Intramuscular triacylglycerols may also be hydrolysed to provide fatty acids for mitochondrial oxidation, particularly during exercise, when hormone-sensitive lipase and other enzymes are activated Mitochondrial LCFA entry is also highly regulated This however does not involve only the malonyl CoA carnitine palmitoyltransferase-I (CPTI) axis Exercise-induced fatty acid entry into mitochondria is also regulated by at least one of the proteins (FAT/CD36) that also regulates plasma membrane fatty acid transport Among individuals, differences in mitochondrial fatty acid oxidation appear to be correlated with the content of mitochondrial CPTI and FAT/CD36 This paper provides a brief overview of mechanisms that regulate LCFA uptake and oxidation in skeletal muscle during exercise and in obesity We focus largely on our own work on FAT/CD36, which contributes to regulating, in a coordinated fashion, LCFA uptake across the plasma membrane and the mitochondrial membrane Very little is known about the roles of FATP1-6 on fatty acid transport in skeletal muscle

Fatty-acid-binding proteins. Occurrence of two fatty-acid-binding proteins in bovine liver cytosol and their binding of fatty acids, cholesterol, and other lipophilic ligands.

Abstract: Fatty-acid-binding proteins (FABPs) are known as cytosolic binding sites for fatty acids and their CoA esters. Radioactively labeled and fluorescent fatty acids were used to locate and identify these proteins in bovine liver cytosol. The occurrence of two species of FABPs was demonstrated and these were designated pI6.0-FABP and pI7.0-FABP according to their isoelectric points in the delipidated state. Oleic acid/FABP binding ratios were 1 with pI6.0-FABP and 2 with pI7.0-FABP. Upon binding of oleic acid the isoelectric points of liganded FABPs shifted to pH 5.0-5.1 in each case. Both proteins were purified by removing nonbinding proteins by acid and heat denaturation and subsequent gel filtration. By making use of the pI shifts observed upon lipidation and delipidation of the binding proteins with ligand fatty acids, final purification was achieved in two fractionations by isoelectric focusing. The binding proteins (Mr 11 800 +/- 1 000) had similar amino-acid compositions (no Trp) and were not covalently modified by carbohydrate and fatty acid. Fatty acids and their CoA esters were complexed by either FABP, cholesterol only by pI-7.0-FABP, though non-stoichiometrically. 16-(9-Anthroyloxy)palmitic acid was bound by pI-7.0-FABP in a 1:1 ratio and precluded the additional binding of a straight-chain fatty acid. Electrophoretic titration curves indicated dissociation of the oleic acid/pI7.0-FABP complex below pH 5.0. It appears that fatty acids and their CoA esters are the foremost binding partners of FABPs in vivo. The results are discussed in terms of a single binding site for fatty acids per molecule FABP.

Fatty acid binding protein. Role in esterification of absorbed long chain fatty acid in rat intestine.

Abstract: Fatty acid binding protein (FABP) is a protein of 12,000 mol wt found in cytosol of intestinal mucosa and other tissues, which exhibits high affinity for long chain fatty acids. It has been suggested that FABP (which may comprise a group of closely related proteins of 12,000 mol wt) participates in cellular fatty acid transport and metabolism. Although earlier findings were consistent with this concept, the present studies were designed to examine its physiological function more directly. Everted jejunal sacs were incubated in mixed fatty acid-monoglyceride-bile acid micelles, in the presence or absence of equimolar concentrations of either of two compounds which inhibit oleate binding to FABP:flavaspidic acid-N-methyl-glucaminate and alpha-bromopalmitate. Oleate uptake, mucosal morphology, and oxidation of [14C]acetate remained unaffected by these agents, but oleate incorporation into triglyceride was inhibited by 62-64% after 4 min. The inhibition by flavaspidic acid was reversible with higher oleate concentrations. The effect of these compounds on enzymes of triglyceride biosynthesis was examined in intestinal microsomes. Neither flavaspidic acid nor alpha-bromopalmitate inhibited acyl CoA:monoglyceride acyl-transferase. Fatty acid:coenzyme A ligase activity was significantly enhanced in the presence of partially purified FABP, probably reflecting a physical effect on the fatty acid substrate or on the formation of the enzyme-substrate complex. Activity of the enzyme in the presence of 0.1 mM oleate was only modestly inhibited by equimolar flavaspidic acid and alpha-bromopalmitate, and this effect was blunted or prevented by FABP. We conclude that in everted gut sacs, inhibition of triglyceride synthesis by flavaspidic acid and alpha-bromopalmitate could not be explained as an effect on fatty acid uptake or on esterifying enzymes in the endoplasmic reticulum but rather can be interpreted as reflecting inhibition of fatty acid binding to FABP. These findings lend further support to the concept that FABP participates in cellular fatty acid transport and metabolism. It is also possible that FABP, by effecting an intracellular compartmentalization of fatty acids and acyl CoA, may play a broader role in cellular lipid metabolism.