Base exchange reactions of the phospholipids in rat brain particles

Abstract

A particulate fraction from rat brain catalyzes the incorporation of [14C]choline, [14C]ethanolamine, and l-[1414C]serine into phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine, respectively. The reaction appears to be energy-independent since Mg2+, CTP, ATP, and NaF have no stimulatory action. The incorporation is inhibited by EDTA and activated by Ca2+. The pH optimum for the incorporation of choline is 9.5, for ethanolamine it is 9.0, and for l-serine it is 8.5. Tris, bicine, and imidazole buffers are inhibitory. The incorporations are inhibited by a variety of structurally related alcohols and are stimulated by isoserine (α-hydroxy,β-aminopropionic acid).

Keywords

• phosphatidylserine
• phosphatidylcholine
• phosphatidylethanolamine
• base incorporation
• isoserine
• Ca2+ stimulation