Food Hygienic Studies of Sulfite (V)

Effects of Sulfite on Nitrate Reductase, Nitroreductase and Methaemoglobin Formation

Abstract

Effects of sulfite on nitrate reductase, nitroreductase activities and methaemoglobin (Met. Hb) formation were reported with the following results. Nitrate reduction by washed cells of Escherichia coli was accelerated by the presence of sulfite in the reaction medium. On the other hand, reduction of O-nitrophenol was diminished by the concentration of 10^-1∼10^-2M of sulfite whereas it was accelerated at 10^-3∼10^-5M. Similar results on the reduction in bouillon culture medium were also observed. Met. Hb formation of rabbit erythrocyte suspension with nitrite showed a decrease with the addition of sulfite as compared with the control containing no sulfite. It was also found that levels of Met. Hb in erythrocyte contacted with nitrite revealed a remarkable tendency to decrease after erythrocyte was pre-incubated with sulfite.