Acetyl-CoA carboxylase (ACC; EC 6.4.1.2) catalyses the formation of malonyl-CoA, which is essential as a metabolic substrate and as a modulator of specific protein activity. Malonyl-CoA is a substrate for fatty acid synthase (FAS), for polyketide synthases (in plants, fungi and bacteria) and for fatty acyl chain-elongation systems. As an allosteric modulator, malonyl-CoA potently inhibits carni...

The base-switched annuloselectivity, namely [2 + 2] and [2 + 2 + 2] selectivity, in the reactions of ethyl malonyl chloride and imines is successfully realized. In the presence of the weak nucleophilic base 2-chloropyridine, the reactions deliver ethyl trans-β-lactam-3-carboxylates as the exclusive [2 + 2] products in up to 93% yields, while with the strong nucleophilic N-methylimidazole as the...

The anthocyanin pattern of artichoke heads (Cynara scolymus L.) has been investigated by high-performance liquid chromatography-electrospray ionization mass spectrometry. For this purpose a suitable extraction and liquid chromatographic method was developed. Besides the main anthocyanins-cyanidin 3,5-diglucoside, cyanidin 3-glucoside, cyanidin 3,5-malonyldiglucoside, cyanidin 3-(3''-malonyl)glu...

This multienzyme complex behaves during protein fractionation, centrifugation, and electrophoresis as a single protein particle of molecular weight 2.3 x 106 (ref. [ 11). The synthesis of fatty acids requires at least six different enzymatic steps which have been demonstrated with the help of model substrates [2]. After transfer of acetyland malonyl-residues from acetylCoA and malonyl-CoA to th...

Acyltransferases determine which extender units are incorporated into polyketide and fatty acid products. The ping-pong acyltransferase mechanism utilizes a serine in a conserved GHSxG motif. However, the role of the conserved histidine in this motif is poorly understood. We observed that a histidine to alanine mutation (H640A) in the GHSxG motif of the malonyl-CoA specific yersiniabactin acylt...

The protein substrates of sirtuin 5-regulated lysine malonylation (Kmal) remain unknown, hindering its functional analysis. In this study, we carried out proteomic screening, which identified 4042 Kmal sites on 1426 proteins in mouse liver and 4943 Kmal sites on 1822 proteins in human fibroblasts. Increased malonyl-CoA levels in malonyl-CoA decarboxylase (MCD)-deficient cells induces Kmal level...

The biosynthesis of membrane lipids is an essential pathway for virtually all bacteria. Despite its potential importance for the development of novel antibiotics, little is known about the underlying signaling mechanisms that allow bacteria to control their membrane lipid composition within narrow limits. Recent studies disclosed an elaborate feed-forward system that senses the levels of malony...

Extracts from human platelets contain the enzymes of de novo fatty acid biosynthesis. The pattern of incorporation of acetate-1-(14)C into fatty acids by intact platelets indicates that these enzymes function in platelets. The level of acetyl-coenzyme A (CoA) carboxylase activity in extracts of platelets from normal subjects is 0.036 +/-0.01 mmumole of malonyl-CoA formed per min per mg of prote...

5-Aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR) is taken up by perfused skeletal muscle and phosphorylated to form 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuraosyl-5'-monopho sph ate (analog of 5'-AMP) with consequent activation of AMP-activated protein kinase, phosphorylation of acetyl-CoA carboxylase, decrease in malonyl-CoA, and increase in fatty acid oxidation. This study...