Fig. 4.

Effect of the GSH concentration on the NO concentration 2 min after injection of GSH. The concentration of NO remaining 2 min after GSH addition (see also Supplementary Fig. S1) in the absence and presence of 5 mM MgCl₂ is plotted against the GSH concentration. Experimental conditions: 1 µM PROLI/NO, varying concentrations of GSH (0.1–5 mM), 1000 U/ml SOD, 0.1 mM DTPA, 0 (white circles, dotted line) or 5 (black circles, continuous line) mM MgCl₂, and 50 mM TEA (pH 7.4) in 0.5 ml at 37 °C. Also included are the results obtained for 2 mM GSH with authentic NO (0.75 mM) in the absence (white square) and presence (black square) of 5 mM MgCl₂. Data are shown ±SEM (n=5).