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STUDIES ON THE CDP‐ETHANOLAMINE‐1,2‐DIGLYCERIDE ETHANOLAMINEPHOSPHOTRANSFERASE OF RAT BRAIN
Author(s) -
Ansell G. B.,
Metcalfe R. F.
Publication year - 1971
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1971.tb11995.x
Subject(s) - ethanolamine , glycerol , microsome , diglyceride , chemistry , phosphatidylethanolamine , biochemistry , plasmalogen , enzyme , chromatography , phosphatidylcholine , phospholipid , membrane
— The ethanolaminephosphotransferase (EC 2.7.8.1) of rat brain is found largely in the microsomal fraction and is active towards both diacyl glycerol and alkenyl acyl glycerol. Manganese ions were found to be more effective activators of the enzyme than magnesium ions at low concentrations. The K m for CDP‐ethanolamine was found to be about 2.5 × 10 −4 M in the presence of either lipid acceptor and the K m for the two lipid acceptors about 1.6 × 10 −3 M. Under the most favourable conditions rates of 270 nmol phosphatidylethanolamine and 70 nmol ethanolamine plasmalogen/mg microsomal protein/h at 39°C were obtained. The effect of temperature on the reaction rate depended on whether diacyl glycerol or alkenyl acyl glycerol was the lipid acceptor. Although diacyl glycerol inhibited the formation of ethanolamine plasmalogen the inhibition was not a simple competitive one. In terms of microsomal protein the activity was maximal during the period of active myelination but at3 days and 150 days of ageitwasat least 50 percent of this maximal activity.