Methemoglobin formation by potassium ferrocyanide in the hemolysate of acatalasemic mice.

: Increased methemoglobin (metHb) formation is harmful to the normal oxygen transport. There are some mechanisms to reduce metHb formation in the erythrocyte. In the present study, effect of catalase (EC 1.11.1.6) on metHb formation by potassium ferrocyanide was examined spectrophotometrically in the hemolysates of acatalasemic, homozygous hypocatalasemic and normal mice. MetHb formation in the hemolysate of acatalasemic mice was significantly higher than that of normal mice. The addition of catalase reduced the metHb level, while superoxide dismutase (SOD) had little effect on it. A negative intimate correlation was observed between the logarithm of catalase activity (PU/gHb) and the metHb level (%) in the hemolysate. 3-Amino-1,2,4-triazole (AT), a specific catalase inhibitor, significantly increased the formation of metHb. These results indicate that hydrogen peroxide is generated in the process of metHb formation by potassium ferrocyanide and that catalase inhibits the metHb formation by destroying the H2O2 produced.