Nicolson T, Mayinger P
Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany.
FEBS Lett. 2000 Jul 7;476(3):277-81. doi: 10.1016/s0014-5793(00)01684-7.
The molecular basis of transbilayer movement or flipping of phospholipids in the endoplasmic reticulum is largely unknown. To circumvent the problems inherent to studies with artificial phospholipid analogs, we studied microsomal flip-flop of endogenous phosphatidylethanolamine in yeast. The transbilayer transport of phosphatidylethanolamine was measured in reconstituted proteoliposomes derived from microsomal detergent extracts. Our results demonstrate that flipping is protease sensitive but does not require metabolic energy. Our assay is the first to use the endogenous substrate of the so-called 'flippase' to study phospholipid translocation in endomembranes and may therefore be crucial for the understanding of the catalytic properties of this elusive enzyme.
内质网中磷脂的跨膜运动或翻转的分子基础在很大程度上尚不清楚。为了规避使用人工磷脂类似物进行研究时固有的问题，我们研究了酵母中内源性磷脂酰乙醇胺的微粒体翻转。在源自微粒体去污剂提取物的重组蛋白脂质体中测量了磷脂酰乙醇胺的跨膜转运。我们的结果表明，翻转对蛋白酶敏感，但不需要代谢能量。我们的测定方法首次使用所谓“翻转酶”的内源性底物来研究内膜中的磷脂转运，因此对于理解这种难以捉摸的酶的催化特性可能至关重要。
