Plasmalogen aldehydes

Identification and Gas-Liquid Chromatographic Behavior of Plasmalogen Aldehydes and Their Acetal, Alcohol, and Acetylated Alcohol Derivatives... 

Also, the primary amine moities of polar lipids catalyze the aldol condensation of Cm-Cig aldehydes resulting from plasmalogen hydrolysis, thus forming a,3-unsaturated aldehydes (l2t). Phosphatidyl ethanolamine reacted with propanal and n-hexanal forming phosphatidyl l-(2-hydroxyethyl)-2-ethyl-3,5-dimethyl pyridinium, and phosphatidyl-1-(2-hydroxy ethyl)-2-hexyl-3,5-dipentyl pyridinium, respectively (125). The peridinium ring is formed by the reaction between one mole of amino-N of phosphatidyl ethanolamine and three moles of n-alkanals. The same reaction took place in the synthesis of substituted pyridines by condensation of carbonyl compounds with ammonia (126, 127). 

The plasmalogens represent an unusual type of glycerophosphatide that has been isolated from animal and plant tissues. Acid hydrolysis of these materials yields long-chain aldehydes and mono-acylated a-glycerophosphate. The long-chain aldehydes originate from vinyl ether structures. The vinyl ether group appears usually (if not always) in... 

The a,jS-unsaturated fatty ether is an aldehydogenie group because its hydrolysis releases an a -unsaturated primary alcohol that readily tautomerizes to an aldehyde. Choline, ethanolamine, and serine plasmalogens are found in cardiac and skeletal muscle, brain, and liver. The biosynthesis of phosphatidylethanolamine is shown in Figure 19-5. 

Fig. 12. Cleavage of the O-alkyl linkage in glycerolipids (A) is catalyzed by (1) a Pte-H4-dependent alkyl monooxygenase, a microsomal enzyme found primarily in liver and intestinal tissues. The hemiacetal shown in this reaction has not been isolated because of its instability. The fatty aldehyde product can be either reduced to a long-chain fatty alcohol by (II) a reductase or oxidized to a fatty acid by (III) an oxidoreductase. Removal of the 0-alk-l -enyl moiety from plasmalogens (B) is catalyzed by plasmalogenase. As with the O-alkyl monooxygenase, the fatty aldehyde can be converted to either the corresponding fatty alcohol or the fatty acid. GPE, sn-glycero-3-phosphoethanolamine.

Plasmalogenases (Fig. 12) hydrolyze the O-alk-l -enyl function of plasmalogens or lysoplasmalogens. The products of this reaction are a fatty aldehyde and either l-lyso-2-acyl-in-glycero-3-phosphoethanolamine (or choline) or s -glycero-3-phosphoethanolamine... 

Liberation of a-Halofatty Aldehydes from Plasmalogens Chanical... 

The masked aldehyde of plasmalogens is not readily metabolized, but plasmaloge-nase activity has been reported (McMaster et al. 1992). The turnover of the vinyl ether aliphatic group is 300-times slower compared to that of turnover of the sn-2 esterified fatty acid and the sn-3 polar head group (Ford and Gross 1994). However, the vinyl... 

Liberation of a-HAioFATTY Aldehydes from Plasmalogens Chemical Identity... 

The characterization of the product of RCS targeting of plasmalogens led to several methods that were developed to both purify and quantify a-halofatty aldehyde. For example, thin-layer chromatography with silica gel G as a solid phase and petroleum ether/ethyl ether/acetic acid (90/10/1) separates a-chlorofatty aldehydes (/f =0.46) and a-bromofatty aldehydes (Rf= 0.58) (Albert et al. 2001, 2002). The confirmation of the structure of 2-chlorohexadecanal and 2-bromohexadecanal using GC-MS following derivatization to its pentafluorobenzyl oxime also proved to be an extremely... 

Albert, C. J., A. K. Thukkani, R. M. Heuertz, A. Slungaard, S. L. Hazen, and D. A. Ford. 2003. Eosinophil peroxidase-derived reactive brominating species target the vinyl ether bond of plasmalogens generating a novel chemoattractant, alpha-bromo fatty aldehyde. J Biol Cfem 278(1 n 8942-.50. 

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