Monomethyl phosphatidylethanolamine

However, PE was the poorest substrate for this reaction. Monomethyl phosphatidylethanolamine (MMPE) was somewhat better, and the products were dimethyl phosphatidylethanolamine (DMPE) and PC. The best substrate was DMPE, and 94% of the product was water-soluble after deacylation, as expected for s/i-glycerol-3-phosphorylcholine. The pH optimum was reported to be 8. The highest amount and highest specific activity for DMPE incorporation into PC was found in the 100,(X)()-g pellet, but significant activity was also found in the 15,(K)0-g pellet. 

Siegel et al. attempted to use the T-jump cryo-TEM technique to directly visualize the intermediate states in the coiuse of the L H2 transition in lipids. The specimen for cryo-TEM was rapidly heated by exposure to the light from a xenon lamp and vitrified to fix possible intermediate states induced by the T-jump. For egg phosphatidylethanolamine, the transition was found to be completed in 9 ms when the specimen was superheated by 20°C. N-monomethylated DOPE showed a slower transition. In both instances no intermediate state could be resolved owing to their lability on the time scale of the method stated to be aroimd 1 ms. 

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