Preparation of fatty acid methyl esters and dimethylacetals from lipids with boron fluoride–methanol

Rapid Preparation of Fatty Acid Esters from Lipids for Gas Chromatographic Analysis.

Direct transesterification of all classes of lipids in a one-step reaction.

Sirtuins are NAD(+)-dependent protein deacetylases. They mediate adaptive responses to a variety of stresses, including calorie restriction and metabolic stress. Sirtuin 3 (SIRT3) is localized in the mitochondrial matrix, where it regulates the acetylation levels of metabolic enzymes, including acetyl coenzyme A synthetase 2 (refs 1, 2). Mice lacking both Sirt3 alleles appear phenotypically normal under basal conditions, but show marked hyperacetylation of several mitochondrial proteins. Here we report that SIRT3 expression is upregulated during fasting in liver and brown adipose tissues. During fasting, livers from mice lacking SIRT3 had higher levels of fatty-acid oxidation intermediate products and triglycerides, associated with decreased levels of fatty-acid oxidation, compared to livers from wild-type mice. Mass spectrometry of mitochondrial proteins shows that long-chain acyl coenzyme A dehydrogenase (LCAD) is hyperacetylated at lysine 42 in the absence of SIRT3. LCAD is deacetylated in wild-type mice under fasted conditions and by SIRT3 in vitro and in vivo; and hyperacetylation of LCAD reduces its enzymatic activity. Mice lacking SIRT3 exhibit hallmarks of fatty-acid oxidation disorders during fasting, including reduced ATP levels and intolerance to cold exposure. These findings identify acetylation as a novel regulatory mechanism for mitochondrial fatty-acid oxidation and demonstrate that SIRT3 modulates mitochondrial intermediary metabolism and fatty-acid use during fasting.

https://escholarship.org/content/qt74b7b8tf/qt74b7b8tf.pdf?t=qag5yr

SIRT3 regulates mitochondrial fatty-acid oxidation by reversible enzyme deacetylation

https://www.jbc.org/content/246/17/5477.full.pdf

Partial Resolution of the Enzymes Catalyzing Oxidative Phosphorylation XXV. RECONSTITUTION OF VESICLES CATALYZING 32Pi—ADENOSINE TRIPHOSPHATE EXCHANGE

Quantitative fatty acid analysis of milk fat by gas-liquid chromatography

Cyclic fatty acid monomers were analyzed by gas chromatography in commercial frying oils, obtained in this country and in the Middle East. Samples were obtained from food outlets in California and Illinois after varying periods of usage. The samples from Egypt and Israel were collected from street vendors frying vegetable patties (known as “fallafel”) in open-air stands. The United States samples ranged from 0.1 to 0.5% cyclic monomers, and from 1 to 8% polar +noneluted thermal oxidation materials. The Middle Eastern samples showed significantly more heat abuse, with values for cyclic monomers from 0.2 to 0.7% and polar materials ranging from 2 to 22%.

Occurrence of cyclic fatty acid monomers in frying oils used for fast foods

Intramolecular fatty acid distribution in the milk fat triglycerides of several species.

Milk lipids were fractionated by silicic acid column chromatography and preparative thinlayer chromatography (TLC). Ceramide monohexoside (CMH), ceramide dihexoside (CDH), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), phosphatidyl serine (PS), and sphingomyelin (Sph) were isolated, and the purity of each was checked by infrared spectroscopy and TLC. The diacylphospholipids were hydrolyzed with phospholipase A and the products separated by TLC. Fatty acid methyl esters were prepared from the various fractions and analyzed by gas chromatography.

L.M. Smith

Papers

Preparation of fatty acid methyl esters and dimethylacetals from lipids with boron fluoride–methanol

Quantitative fatty acid analysis of milk fat by gas-liquid chromatography

Occurrence of cyclic fatty acid monomers in frying oils used for fast foods

Intramolecular fatty acid distribution in the milk fat triglycerides of several species.

Fatty acids of bovine milk glycolipids and phospholipids and their specific distribution in the diacylglycerophospholipids.