FIGURE 6.

Effect of pH on NO generation from cytoglobin-mediated nitrite reduction under near-anaerobic conditions. Measurements were performed with 10 μm Cygb in the presence of 1 mm nitrite at pH 5.5 in 5 ml of MES (50 mm) or at pH 6.0, 6.5, 7.0, 7.5, or 8.0 in 5 ml of phosphate buffer at 37 °C under anaerobic conditions. The maximum rates of NO production were measured by the chemiluminescence NO analyzer under anaerobic conditions. A, chemiluminescence measurements of NO generation from 1 mm nitrite with 10 μm Cygb at pH 5.5 (a), pH 6.5 (b), and pH 7.0 (c) or without addition of Cygb at pH 5.5 (d). B shows the graph of pH-dependent NO generation rates from pH 5.5 to 8.0.