- A lysophospholipase D pathway in the metabolism of ether linked lipids in brain microsomes
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Microsomal preparations from rat brain in the presence of Mg2+ hydrolyzed the ethanolamine, choline, and phosphate moieties from 1 [1 14C]hexadecyl sn glycero 3 phosphorylethanolamine, 1 [1 14C]hexadec 1 enyl sn glycero 3 phosphorylethanolamine, and 1 [1 14C]hexadecyl sn glycero 3 phosphorylcholine. Studies of the hydrolysis of 1 [1 14C]hexadecyl sn glycero 3 phosphorylethanolamine in this system indicated that the ethanolamine moiety was first removed by a phosphodiesterase to form 1 [1 14C]hexadecyl glycero 3 phosphate which was then dephosphorylated to form 1 [1 14C]hexadecylglycerol. Only minimal hydrolysis occurred when the 2 positions of the substrates were acylated; otherwise the phosphodiesterase activity was similar to that of phospholipase D from plants. The occurrence of such a lysophospholipase D pathway has not been previously reported. When Ca2+ (5 mM) was added to the system instead of Mg2+ (5 mM), little, if any, stimulation occurred; higher concentrations of Ca2+ (25 mM) inhibited the reaction. Therefore, this reaction does not appear to be related to the Ca2+ stimulated base exchange reaction found in the brain by others.
- Wykle,Schremmer
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p. 1742 - 1746
(2007/10/13)
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