Detergent Fractionation of Glutaraldehyde-fixed Spinach Thylakoids

In 1969, Hallier and Park (5) showed that glutaraldehydefixed spinach thylakoids retained appreciable Hill reaction activity after extraction with 1% Triton X-100. The resistance of the fixed membranes to detergent destruction led them to suggest that such membranes might be favorable starting material for subsequent detergent fractionation studies. They postulated that cross-linking of membrane proteins would allow isolation of the larger membrane subunits identified by electron microscopy (8, 9). This paper reports an exploration of this suggestion. We investigated whether fixed membranes fragment differently from unfixed membranes when treated with various detergents and whether the fragments so liberated could be related morphologically to structures observed in the intact thylakoid.