Specific Transport of Inorganic Phosphate and C 3 ‐ and C 6 ‐Sugar‐Phosphates across the Envelope Membranes of Tomato ( Lycopersicon esculentum ) Leaf‐Chloroplasts, Tomato Fruit‐Chloroplasts and Fruit‐Chromoplasts

Abstract

Plastidial envelope membranes were isolated from tomato (Lycopersicon esculentum) leaves and green and red tomato fruits by isopycnic discontinuous sucrose density gradient centrifugation. Solubilized envelope membrane proteins were reconstituted into liposomes. Transport measurements revealed that the phosphate translocator from tomato leaves transports inorganic phosphate, 3-phosphoglycerate and triosephosphates. The phosphate translocators of green and red fruit plastids catalyze, in addition to the transport of these substrates, also the transport of glucose-6-phosphate, glucose-1-phosphate and phosphoenolpyruvate.