Phosphatidyl Inositol and Complex Inositides in Autolysed Baker's Yeast

Abstract

Complex glycosphingolipids present in extracts of toluene-autolysed baker's yeast were removed by solvent fractionation with a I : I mixture of chloroform and methanol. Phospholipids which were soluble in chloroform-methanol 1:1, but insoluble in isopropanol, were converted into the sodium salts, and crystallization of these from ether-methanol gave phosphatidyl Inositol, free from cardiolipin.Further purification was effected by adsorbing the phospholipid on silicic acid, and developing the initially dry column with chloroform-methanol-water. The glycosphingolipid fraction was resolved into residual phosphatidyl inositol and two glycolipid components, by chromatography on Florisil. These complex inositides possibly derive from the yeast cell wall, and, if so, they may influence the hydrophllic/ hydrophobic character of the cell surface if located on the outer side or, if on the inner side, may constitute a link between the cell membrane and the cell wall.