In brief, samples
were incubated with BAPNA (0.5 mg.ml−1) for 10 min at 37.5 °C.
The reactionwas stopped with 0.2MHCl prior to the addition of sodium
nitrite (0.1%), ammonium sulphamate (0.5%) and N-(1-Naphthyl) ethylenediamine
dihydrochloride (0.05% prepared in 95% ethanol) at 3 min
intervals