High performance liquid chromatography bonding structure

Certain classes of lipids are susceptible to degradation under specific conditions. For example, all ester-linked fatty acids in triacylglycerols, phospholipids, and sterol esters are released by mild acid or alkaline treatment, and somewhat harsher hydrolysis conditions release amide-bound fatty acids from sphingolipids. Enzymes that specifically hydrolyze certain lipids are also useful in the determination of lipid structure. Phospholipases A, C, and D (Fig. 10-15) each split particular bonds in phospholipids and yield products with characteristic solubilities and chromatographic behaviors. Phospholipase C, for example, releases a water-soluble phosphoryl alcohol (such as phosphocholine from phosphatidylcholine) and a chloroform-soluble diacylglycerol, each of which can be characterized separately to determine the structure of the intact phospholipid. The combination of specific hydrolysis with characterization of the products by thin-layer, gas-liquid, or high-performance liquid chromatography often allows determination of a lipid structure. 

Aqueous and methanolic solutions of cyclodextrins have been employed as mobile phases in high performance liquid chromatography (HPLC), and as stationary phases by bonding the cyclodextrin to silica packing by several workers (1-8). They have been shown to be especially suitable for separation of structural isomers, cis-trans geometric isomers, and enantiomers. Cyclodextrins (CD) are toroidal-shaped, cyclic, oligosaccharides made up of o-l,4 linked,... 

The discovery of anandamide (arachidonoyl ethanolamide, AEA) and of its manifold roles in the central nervous system and in the periphery (reviewed in refs. 1 and 2) prompted several researchers to develop analytical methods to assay and characterize the activity of the enzymes responsible for AEA metabolism in various cells and tissues. Fatty acid amide hydrolase (arachidonoyl ethanolamide amidohydrolase, EC 3.5.1.4 FAAH) has emerged as the key AEA hydrolase, showing a molecular mass of approx 64 kDa and an optimum pH of around 9.0 (3). Recently, FAAH has been crystallized,and its three dimensional structure has been determined at 2.8A resolution (4). This enzyme cleaves the amide bond and releases arachidonic acid and ethanolamine. High-performance liquid chromatography (HPLC) is the most widely used method to determine FAAH activity from different sources. We developed a new method (5) based on reversed-phase (RP)-HPLC and on-line scintillation counting, which combines the need for high resolution, reproducibility, and sensitivity... 

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