Fig. 2.

Nitric oxide production from a mixture of ascorbate and nitrite as a function of pH. The reaction vessel was supplemented with 250 µM of ascorbate and 20 µM of nitrite at a pH of 7.4. The vessel was coupled to an amiNO^® sensor (selective for ^•NO measurements) and to a pH meter. Current was allowed to stabilize. Then, pH was slowly acidified until it reached the value of 6.51 (a value that can be reached in vivo under hypoxic conditions). At this pH value, current increased indicating that ^•NO was being produced. Maximum concentration of ^•NO obtained in these conditions was 118 nM.