Isolation and identification of chloroplast lipids

Glycerolipids of photosynthetic organisms are accounted for largely by thylakoid membrane lipids consisting of chloroplast-specific glycolipids, such as monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and a sole phospholipid, phosphatidylglycerol. In this chapter, methods for characterization of lipids from plant cells are described. The methods include extraction of total lipids from cells, separation of these lipids into individual lipid classes by thin-layer chromatography (TLC), and identification of respective lipid classes by their mobility. We also show methods for determination of compositions of constituent fatty acids, distribution of fatty acids between sn-1 and sn-2 positions, and contents of individual lipid classes by gas-liquid chromatography. These methods are applicable to isolated chloroplasts or membrane fractions such as thylakoid membranes.