EVIDENCE FOR A DIRECT INTERACTION OF SUPEROXIDE ANION-RADICAL WITH CARNOSINE

Using photochemiluminescence, the interaction between carnosine and su peroxide anion was measured directly. Carnosine at physiological conce ntrations decreased the amplitude of luminol chemiluminescence like su peroxide dismutase (SOD) did, and prolonged the lag-period of the chem iluminescence similar to the effect of ascorbic acid. From the interac tion of nitro blue tetrazolium with superoxide anion generated by the xanthine oxidase system, the constant for interaction of carnosine wit h 0(2)(radical anion) was calculated to be 10(5) M-1 sec(-1) The possi ble biological significance of the quenching of superoxide anion by ca rnosine is discussed.