Kinetics of the Oxidation of NADH by Methylene Blue in a Closed System

Article abstract of DOI:10.1021/j100159a054

The kinetics of anaerobic oxidation of nicotinamide adenine dinucleotide (NADH) by methylene blue was investigated in phosphate and glycine buffers with an excess of NADH in a closed system.The reaction is first order with respect to the concentration of methylene blue.The observed rate constant is pH independent over the pH range of 7.0-10.6 and increases with NADH concentration in a saturated mode.The oxidation process was also investigated under aerobic conditions in a closed system.Applying the steady-state approximation to methylene blue, the rate constant for reoxidation of the reduced form of methylene blue by oxygen was esti mated to be 1.62 x 10² M^-1s^-1 at pH 9.0 at 25 deg C.The implications of the present results for NAD(1+) regeneration and oscillatory reactions are noted.