Isolation of protein(s) containing chloride ion transport activity from thylakoid membranes

Extracts of detergent-treated thylakoids, when reconstituted into azolectin/cholesterol/dicetyl phosphate vesicles, stimulate chloride ion efflux as measured with a Cl--sensitive electrode. This stimulation is inhibited by piretanide, an active chloride ion transport inhibitor in fish intestinal epithelia. This stimulation is also abolished by pretreatment of extracted proteins with trypsin. Antiserum raised to efflux-active proteins inhibits a cation-driven Cl- influx in nonenergized thylakoids, as measured by a flow dialysis technique.