Williams M, Harwood J L
School of Molecular and Medical Biosciences, University of Wales College of Cardiff, Wales, U.K.
Biochem J. 1994 Dec 1;304 ( Pt 2)(Pt 2):463-8. doi: 10.1042/bj3040463.
Olive (Olea europaea L.) callus cultures were incubated with [2-14C]ethanolamine and [Me-14C]choline in order to study phospholipid synthesis. Radioactivity from [Me-14C]choline was shown to be incorporated into the phosphatidylcholine via the CDP-base pathway. [2-14C]Ethanolamine was primarily incorporated into phosphatidylethanolamine, but significant radio-activity was also detected in phosphatidylcholine, indicating the operation of a methylation route. Incubation with [2-14C]ethanolamine indicated that phosphatidylcholine and phosphatidylethanolamine incorporated radiolabel over a similar time course. This led us to investigate the possibility that phosphatidylcholine was being synthesized by a methylation pathway distinct from the direct methylation of phosphatidylethanolamine. There was extensive incorporation of [2-14C]ethanolamine into different components of the aqueous phase of the incubations, within which phospho-base derivatives of ethanolamine were prominent. These intermediates were identified and provided evidence for the operation of an alternative methylation pathway via phosphodimethylethanolamine for the biosynthesis of phosphatidylcholine in olives.
为了研究磷脂合成，将油橄榄（Olea europaea L.）愈伤组织培养物与[2-¹⁴C]乙醇胺和[甲基-¹⁴C]胆碱一起孵育。结果表明，[甲基-¹⁴C]胆碱的放射性通过CDP-碱基途径掺入磷脂酰胆碱中。[2-¹⁴C]乙醇胺主要掺入磷脂酰乙醇胺中，但在磷脂酰胆碱中也检测到显著的放射性，这表明存在甲基化途径。用[2-¹⁴C]乙醇胺孵育表明，磷脂酰胆碱和磷脂酰乙醇胺在相似的时间进程中掺入放射性标记。这促使我们研究磷脂酰胆碱是否通过与磷脂酰乙醇胺直接甲基化不同的甲基化途径合成。[2-¹⁴C]乙醇胺广泛掺入孵育水相的不同组分中，其中乙醇胺的磷酸碱基衍生物很突出。这些中间体被鉴定出来，并为通过磷酸二甲基乙醇胺的替代甲基化途径在油橄榄中生物合成磷脂酰胆碱提供了证据。
