Studies on the Efficiency of Energy Conservation in the Initial Stages of Photophosphorylation
The first section of the thesis is an investigation of the accessibility of the thylakoid lumen to exogenous buffers, and the effects of added buffers on presteady state phosphorylation. Using the method of silicon oil centrifugation to measure uptake of radioactively labelled compounds, we estimated permeability coefficients for sorbitol, sucrose, and Tris, Tricine, and MOPS buffers and found these compounds to be only slowly permeant. However, incubation of thylakoids in Tricine for one hour allowed enough buffer to be taken up to generate a predictable lag in the onset of ATP synthesis. When membranes so incubated were illuminated by a train of single turnover flashes, ATP synthesis began long before the added Tricine could have been titrated.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign