Unexpected dependence on pH of NO release from Paracoccus pantotrophus cytochrome cd1.

A previous study of nitrite reduction by Paracoccus pantotrophus cytochrome cd(1) at pH 7.0 identified early reaction intermediates. The c-heme rapidly oxidised and nitrite was reduced to NO at the d(1)-heme.

Stopped-flow Fourier transform infrared spectroscopy allows continuous monitoring of azide reduction, carbon monoxide inhibition, and ATP hydrolysis by nitrogenase.

Stopped-flow FTIR spectroscopy was used to monitor continuously the pre-steady- and steady-state phases of azide reduction by nitrogenase and the accompanying hydrolysis of ATP. This was characterized by a ca. 1.