Plasmalogen synthesis methylation

Although the mitochondria are the primary site of oxidation for dietary and storage fats, the peroxisomal oxidation pathway is responsible for the oxidation of very long-chain fatty acids, jS-methyl branched fatty acids, and bile acid precursors. The peroxisomal pathway also plays a role in the oxidation of dicarboxylic acids. In addition, it plays a role in isoprenoid biosynthesis and amino acid metabolism. Peroxisomes are also involved in bile acid biosynthesis, a part of plasmalogen synthesis and glyoxylate transamination. Furthermore, the literature indicates that peroxisomes participate in cholesterol biosynthesis, hydrogen peroxide-based cellular respiration, purine, fatty acid, long-chain... 

A genus of bacteria, termed the Sphingobacterium, produces sphingolipids by a pathway similar to that in mammals. Clostridia produce plasmalogens (l-alk-l -enyl lipids) by an anaerobic pathway clearly different from the Oj-dependent pathway in mammals (Chapter 9). Branched-chain fatty acids are also found in which the methyl group is inserted post-synthetically into the middle of the chain, in a manner analogous to cyclopropane fatty acid synthesis (Section 5.5). S-adenosylmethionine is also the methyl donor for these reactions. The biochemistry surrounding the formation of these and many other bacterial phospholipids remains to be elucidated. 

The synthesis of ether phosphatidylethanolamines is analogous to that for the formation of the corresponding phosphatidylcholines (Rosenthal, 1975). The iV-methyl-and AW-dimethyl derivatives have been synthesized from their corresponding phosphatidic acids (Aneja et aL, 1970). The formation of AT-acylphosphatidylethanolamines and other analogues is detailed by Slotboom and Bonsen (1970) and that of ethanolamine plasmalogens in Section 7.5.8. 

The data of the present work indicate that rat brain microsomes are able to methylate stepwise phospholipids to form phosphatidylcholine (Ptd-choline) and in addition to produce choline plasmalogen by similar pathway. The rate of synthesis of Ptd-choline by the... 

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