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Phospholipid Flip-Flop

In general, cell membranes have an uneven distribution of phospholipids at each membrane surface. For example, most of the phosphatidylserine and phosphatidylethanolamine in a red blood cell is found in the cytoplasmic side of the cell membrane. There is good evidence that this uneven distribution is maintained by membrane-bound enzymes known as flippases , which catalyze the translocation of phospholipids from one side of the membrane to the other. At present there is no information on how these enzymes operate at the molecular level. In an effort to provide some chemical insight, as well as produce some useful functions, we have invented several artificial scramblases for various phospholipids and shown that they can trigger biological responses such as blood clotting and phagocytosis.