A method of column chromatographic isolation of major phospholipid components on Escherichia coli

For the column chromatographic isolation of individual phospholipids from the total phospholipid mixture, silicic acid, DEAE cellulose, alumina and others, have been used as adsorbent. However, it must be emphasized that silicic acid (1, 2, 3, 4) is the most useful adsorbent for the separation of the total phospholipid mixture from each other in reasonable purity. VAN DEENEN reported that pure phosphatidyl glycerol was obtained from the lipid fraction of spinach leaves after repeated chromatography on silicic acid column (5). The phospholipid extracted from Escherichia coli B consists of abundant phosphatidyl ethanolamine (70-80 %), cardiolipin, phosphatidyl glycerol and other minor components as described in the previous paper (6). The high percentage content of phosphatidyl ethanolamine renders it difficult to separate the phospholipids by the column chromatography. Therefore, repeated chromatographies on the silicic acid column treated with sodium bicarbonate (7) and normal silicic acid column were employed for the isolation of the major components from the total phospholipid of E. coli B. Stepwise elution (4) was carried out with chloroform containing increasing proportions of methanol, and the eluent was divided into several fractions according to experience with thin-layer chromatography.