(A) The reaction contained 1 mM EDTA in 5 mM potassium phosphate (pH 7), 250 uM NADPH, 50 nM GR, 1 mM HEDS and 5 uM of reduced CLIC1 (WT), CLIC1-C24A, CLIC1-C24S or CLIC1-C59A. The mixture was incubated for 5 mins at 37°C before initiation of the reaction with the addition of 1 mM GSH followed by monitoring NADPH absorbance at A340 nm. Error bars represent the S.E. of at least three experimental repeats. (B) A reaction of 5 uM of CLIC1 (WT) reduced monomer or CLIC1-C59A protein, 250 uM NADPH, HEDS (0, 0.25, 0.5, 1, 2, 4 or 6 mM) and 50 nM GR. The reaction was initiated by the addition of 1 mM GSH and the absorbance of NADPH was monitored at A340 nm. The reaction conditions where 5 mM potassium phosphate with 1 mM EDTA, pH 7, at 37°C.