Using BSA（bovine serum albumin） as nitrated substrate and peroxynitrite as nitrification reagent

the inhibition effects of melatonin and rutin on protein nitration were investigated.It was observed that the optimum conditions for complete nitration were pH 7.2

temperature 37 ℃

90 min for reaction time and peroxynitrite concentration of 6.0×10-4mol/L.Under these conditions

various concentrations of melatonin and rutin were used for test at different time point.The data displayed that addition of melatonin or rutin before the process can efficiently retard the reaction

and 5.0×10-5 mol/L melatonin or rutin led to 80.7% and 52.4% reduction of maximum nitration respectively.The rate of inhibition was stable with increasing concentration of melatonin

but decreased after slight increase with more rutin.On the whole

melatonin had the better effect on nitration inhibition than rutin with same concentration.