 HOME :: CHAPTER 6 :: Topic 6.6  Topic 6.6  Transport Studies
with Isolated Vacuoles and Membrane Vesicles  Just as studies
with isolated thylakoid membranes led to the elucidation of the
electron transfer reactions of photosynthesis (see textbook
Chapter 7), the development of techniques for isolating
functionally competent tonoplasts and plasma membranes has
enabled scientists to study the transport reactions of these
membranes in vitro (Sze 1985; Jahn et al. 2001). The use of
isolated membrane vesicles to study transport avoids
interference from metabolism. Since the contents of the vesicles
can be fairly readily exchanged, the concentrations of solutes
on each side of the membrane can be better defined. Two types of
preparations have been used: intact vacuoles, and isolated
plasma membrane or tonoplast vesicles.  Isolating Intact
Vacuoles from Protoplasts  When protoplasts prepared by
enzymatic digestion of the cell walls are maintained in the
plasmolyzed state by incubation in medium containing a suitabl