Phosphatidylethanolamine, hydroperoxide

Phosphatidylethanolamine, hydroperoxide determination, 675, 683-4, 686, 690 PhosphatidyIglycerol, hydroperoxide determination, 690 Phosphatidyhnositol, hydroperoxide determination, 675, 683-4, 686 Phosphatidylserine... 

Miyazawa, T., Suzuki, T., Eujimoto, K. and Yasuda, K. Chemiluminescent simultaneous determination of phosphatidylcholine hydroperoxide and phosphatidylethanolamine hydroperoxide in the liver and brain of the rat. J. Lipid Res. 33, 1051-1058 (1992). 

Browning Reactions. The fluorescent components formed in the browning reaction (8) of peroxidized phosphatidylethanolamine are produced mainly by interaction of the amine group of PE and saturated aldehydes produced through the decomposition of fatty acid hydroperoxides. 

The hydroperoxides of various phospholipids, such as phosphatidylcholine (PC— OOH, 155), phosphatidylserine (PS—OOH), phosphatidylethanolamine (PE—OOH), phos-phatidylinositol (PI—OOH) and cardiolipin (CL—OOH), can be determined by HPLC-ELD on a polar LC—NH2 column, using as mobile phase a MeOH//-PrOH/40 mM aqueous NaH2P04 mixture (61 30 9 by volume). ELD is by the hanging Hg drop electrode method set at —150 mV vs. SCSE. The relative mobility for the given chromatographic system is shown in equation 68, which is almost a reversal of the order shown in equation 63 for HPTLC. The LOD varies from about 0.5 to 1.0 pmol, depending on the class of phospholipid hydroperoxide . ... 

P Therond, M Couturier, JF Demelier, F Lemonnier. Simultaneous determination of the main molecular species of soybean phosphatidylcholine or phosphatidylethanolamine and their corresponding hydroperoxides obtained by lipoxygenase treatment. Lipids 28 245-249, 1993. 

Amino groups of phospholipids, particularly of phosphatidylethanolamine or serine, react with reducing sugars, osones, and other products of sugar degradation to form brown melanoidins. The pathway via Amadori compounds is similar to the case of amino acids (Utzmann and Lederer, 2001). They thus contribute to the darkening of phospholipid concentrates on storage. Melanoidins are partially bleached by lipid hydroperoxides. 

The direct separation of phosphohpidhydroperoxides has now been achieved by further advances in HPLC and increased sensitivity by chemiluminescence detection. By reverse-phase HPLC, the hydroperoxides of phosphatidylcholine and phosphatidylethanolamine were separated and determined in stored spray-dried eggs (2.4. 4%), fresh ground meat (0.2%), and raw fish (0.4%). Silica HPLC with post-column chemiluminescence detection has been used to determine phospholipid hydroperoxides in human blood plasma and in the low-density lipoprotein fraction. 

Schiff base compounds formed by the interaction of oxidation products with proteins, phospholipids and nucleic acids produce chromophores showing characteristic fluorescence spectra. The Schiff base formed between malonaldehyde and amino acids is attributed to the conjugated structure -NH=CH-CH=CH-NH-. Lipid-soluble fluorescence chromophores are produced from oxidized phospholipids and from oxidized fatty acid esters in the presence of phospholipids. These chromophores have fluorescence emission maxima at 435-440 nm and excitation maxima at 365 nm. The Schiff base of malonaldehyde and phospholipids has a higher wavelength maximum for emission (475 nm) and excitation (400 nm). The interaction between oxidized arachidonic acid and dipalmityl phosphatidylethanolamine produce similar fluorescence spectra (maximum excitation at 360-90 nm and maximum emission at 430-460 nm). The products from oxidized arachidonic acid and DNA have characteristic fluorescence spectra, with excitation maximum at 315 nm and emission maximum at 325 nm. Similar fluorescence spectra, with excitation maximum at 320 mn and emission maximum at420 nm, are obtained from the interactions of either lipid hydroperoxides or secondary oxidation products with DNA in the presence of metals and reducing agents, or different aldehydes, ketones and dimeric compounds from oxidized linolenate. Therefore, the Schiff base produced from various oxidized lipids and phospholipids and DNA may be considered to be due to a mixture of closely related chromophores. 

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