Localization of prenylquinones in the envelope of spinach chloroplasts

The isolated and purified chloroplast envelope of spinach leaves contains, besides carotenoids, several prenylquinones as basic constituents: plastoquinone-9, phylloquinone K1, alpha-tocoquinone and the chromanol, alpha-tocopherol. The relative quinone and carotenoid composition of the envelope differs distinctively from that of the thylakoid membranes. The possible role of prenylquinones in metabolic envelope activities and the mediator function of the envelope in prenylquinone biosynthesis are discussed.