Revue bibliographique sur la biosynthese, la degradation et les aspects specialises recents du metabolisme des acides gras

Fatty Acid Metabolism

The formation of flavor in fermented beverages is due to various biosynthetic mechanisms. In wine, flavors arise as the result of compounds: 1. Originating from the native fruit (grap) 2. Which are formed or altered during the various processes employed in production 3. Which are developed or transformed by yeast during fermentation 4. Arise during the aging process In this review the results of investigations on the development of flavors in grape and wine will be discussed. Special attention will be devoted to the effects of specific processes in winemaking on the development of flavor.

Flavor composition of wines: a review.

Two isoenzymes of p-coumarate: CoA ligase were isolated from cell suspension cultures of soybean (Glycine max L., var. Mandarin). Separation and partial purification of the enzymes were achieved by precipitation with MnCl2 and (NH4)2SO4, and column chromatography on DEAE-cellulose, Sephadex G-100 and hydroxyapatite. The isoenzymes had approximately the same molecular weight, but differed significantly with respect to their substrate specificity, their inhibition constants for AMP, their dependence on pH and ionic strength for optimum activity, and their fractionation pattern during the purification procedure or upon analytical disc-gel electrophoresis. Both coumarate: CoA ligases were specific for the activation of various substituted cinnamic acids. Of the cinnamic acids tested, ferulic, sinapic, 5-hydroxyferulic, p-coumaric, and caffeic acids were the substrates with the lowest apparent Km values (on all the order of 1 to 4 x 10(-5) M) for isoenzyme 1. The lowest apparent Km values (from about 1 to 9 x 10(-5) M) for isoenzyme 2 were obtained for caffeic, p-coumaric, m-coumaric, and o-coumaric acids. Sinapic acid and several methoxycinnamic acids were efficient substrates of isoenzyme 1 but were not activated at all by isoenzyme 2. The possible roles of the two p-coumarate: CoA ligase isoenzymes in the phenylpropanoid metabolism of the cell cultures are discussed.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1975.tb03999.x

Isoenzymes of p-coumarate: CoA ligase from cell suspension cultures of Glycine max.

Publisher Summary
This chapter discusses triacylglycerol biosynthesis. The outstanding problems in oil biosynthesis are numerous and offer many exciting challenges that are still of a sufficiently diverse nature to satisfy the interests and demands of most biochemists. A particularly major contribution will be the purification of those proteins that are present in the endoplasmic reticulum of the developing seed and that catalyze the synthesis of triacylglycerol from glycerol phosphate and regulate the acyl quality of the final oil. The solubilization and purification of membrane-bound enzymes is an active area of research and still has many technical problems to overcome. The microsomal membrane from the developing oil seed offers a fundamental system that, because of its specialized nature, is most abundant in those enzymes associated with lipid metabolism. In the longer term, success in purifying the enzymes of triacylglycerol synthesis leads to the preparation of antibodies, mRNA, cDNA, and the ultimate production of cloned genes.

8 – Triacylglycerol Biosynthesis

Publisher Summary This chapter discusses fatty acid activation Most cells can metabolize fatty acids The most important pathways are β-oxidation to acetyl-CoA; esterification with glycerol phosphate, glycerol derivatives, sphingosine, glycol, and long-chain alcohols; chain elongation; desaturation; and α and ω oxidation Fatty acid molecules are completely ionized at physiological pH values The carboxylate ion is chemically unreactive toward nucleophilic substitution Esters, thioesters, and acid anhydrides, in which both the carboxylate resonance and the negative charge on the carboxyl group disappear, are more reactive Both microsomal and mitochondrial long-chain fatty acid activation is stimulated by the presence of high concentrations of several salts Both activities are also strongly stimulated by the addition of the particle-free supernatant from several rat tissues Purified mammalian acyl-CoA synthetases are very specific in their nucleotide requirement

K.P. Huang

Papers

Fat metabolism in higher plants: XLIV. Fatty acid synthesis by a soluble fatty acid synthetase from Solanum tuberosum

Fat metabolism in higher plants. XLI. Properties of potato acetyl coenzyme A synthetase.