KCN-induced urinary chemiluminescence (UCL): inhibition by ascorbic acid.

Addition of KCN or H2O2 to normal human urine resulted in chemiluminescence (CL). The CL increased with increasing concentrations of KCN and H2O2 and with increasing pH of the reaction mixture. KCN-induced UCL was markedly inhibited by exogenously added ascorbic acid (AA) and to varying degrees by glucose, albumin, tryptophan, hemoglobin and histidine. In contrast H2O2-induced UCL was significantly inhibited only by tryptophan. Mannitol and ethanol (hydroxyl radical scavengers) had little effect on either KCN-or H2O2-induced UCL. The KCN-sensitive and the H2O2-sensitive components were eluted in different positions from a Sephadex G15 column indicating chemically distinct compounds with molecular weights of less than 1500 daltons. We conclude that the UCL produced by H2O2 and KCN arise via interactions with chemically distinct compounds present in the urine.