Highly sensitive fluorimetic determination of gluthione based inhibitory effect on multienzyme redox system

A highly sensitive spectrofluorimetric method for the determination of reduced glutathione (GSH,γ-l-glutamyl-l-cysteinylglycine) based on its inhibitory effect on hemoglobin activity was developed. Multienzyme redox system is the most important biological oxidation process in cellular respiration chain. Under the action of hemoglobin, NADH can be oxidized by hydrogen peroxide (H2O2) to form a dimmer that is optimally fluorescent. Under the optimum conditions, the degree of inhibitory effect was linear to the GSH concentration in the range of 5.00 × 10−8 to 9.60 × 10−6 mol l−1. The relative standard deviation was 3.70% for 11 determinations of 5.00 × 10−6 mol l−1 GSH and the detection limit was 8.00 × 10−9 mol l−1. Further experimental results revealed that the inhibition of GSH on this system was of the competitive type.