Proton pumping behavior of stentorin I incorporated into phospholipid vesicles

Abstract

Organic solvent soluble protein, stentorinI was extracted by acetone and reconstituted with phosphatidylcholine to form vesicles which on illumination translocated protons. For the calculation of transported amount of protons, estimations of internal volume and permeability coefficient were made. As a results, proton pumping activity of stentorinI was influenced by the ratio of lipid to protein, and 0.2 g of H$^+$ was transported by 1 mole of stentorinI until a new equilibrium was reached. From the digestion of stentorinI incorporated into phospholipid vesicles with protease, stentorinI is considered to exist in the hydrophobic core of model membrane.