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Glycerophosphorylcholine phosphocholine phosphodiesterase activity of rat brain myelin
Author(s) -
Kanfer J. N.,
McCartney D. G.
Publication year - 1989
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490240214
Subject(s) - phosphocholine , phosphodiesterase , myelin , neuroscience , chemistry , pharmacology , microbiology and biotechnology , biology , biochemistry , central nervous system , enzyme , phospholipid , phosphatidylcholine , membrane
Myelin isolated from rat brain possessed the ability to release phosphorylcholine from glycerophosphoryl‐choline, and this activity was enriched 3.2‐fold over that of the original homogenate. This glycerophosphorylcholine phosphocholine phosphodiesterase activity had a pH optimum at 9.5, had a K m of 0.2 mM, and a V max of 150 nmoles/mg protein/hr. The enzyme had a specific requirement for Zn 2+ with an optimum concentration at 0.25 mM. Maximum enzyme activity was at 50°C and an Arrhenius plot showed a breakpoint at 40°. p ‐Nitrophenylphosphorylcholine was also hydrolyzed by purified myelin and was a competitive inhibitor of glycerophosphorylcholine phosphocholine phosphodiesterase activity with a K i of 0.075 mM. Glycerolphosphorylethanolamine was hydrolyzed only 5% compared with GPC, but it was not an inhibitor.