Prenylquinone profiling in whole leaves and chloroplast subfractions

Prenylquinones are indispensable molecules in plants and animals. In plants, phylloquinone (vitamin K) and plastoquinone are electron carriers during photosynthesis in chloroplasts, whereas tocopherol (vitamin E) functions as a lipid antioxidant. The biosynthetic pathways of the prenylquinones have been largely characterized but the mechanisms regulating their production and distribution in various subcompartments of the chloroplast are only starting to emerge. Research on chloroplast lipid droplets (plastoglobules) has unraveled a complex network of intersecting prenylquinone metabolic pathways that are providing unprecedented insight into the regulatory processes. In this chapter, we describe how to isolate chloroplast membrane fractions, in particular the plastoglobule lipid droplets, and how to profile the prenylquinones that are contained in these fractions.