ISOLATION AND FRACTIONATION OF LEAF PHOSPHATIDES

Abstract

Methods are described for the extraction of total lipids (including pigments) from leaves, under conditions minimizing the action of phosphatidase C on the phosphatides, and for the fractionation of the phosphatide components. The lipids were extracted with hot i-propanol, partitioned into chloroform, and freed from water-soluble substances by washing with water. Chromatography of the lipids on silicic acid – Celite columns yielded a pigment plus non-phosphatide fraction and the following four phosphatide fractions: Fraction I, consisting of inositol–carbohydrate phosphatides; Fraction II, containing mostly phosphatidyl ethanolamine, and some phosphatidyl serine; Fraction III, an unknown phosphatide; and Fraction IV, consisting predominately of phosphatidyl choline. Although the analytical data and the products of hydrolysis of the fractions indicate that complete resolution of the phosphatides has not been achieved, the methods described should be useful as a preliminary group fractionation, prior to further separation and purification steps. The presence of inositol phosphatides in leaves is reported here for the first time.