Preliminary contribution to the complex reduction processes involving mitomycin C

Electrochemical studies indicated that between pH 5 and 10 the antibiotic a nd cancerostatic agent mitomycin C is present in two forms in equilibrium T he quinonoid form is reversibly reduced in wave i(1), the other form irreve rsibly in wave i(2) at - 0.3 V more negative potentials. The conversion of the nonquinonoid form into the quinone is acid catalyzed. The hydroquinone formed in i(1) is converted into two species reduced in waves i(4) and i(5) . Further contribution of electroanalytical investigations is the distinction of three hydrolytic processes with considerably different rates: A very fa st one at pH 4-5, a slower one at pH 2-3.5, and a faster one at pH < 2. Pro ducts of all three hydrolytic processes are reduced in the same potential r ange. In the same potential range is also reduced the product, formed by a fast reaction from the two-electron reduction product of mitomycin C. The e lectrochemical reactivity thus parallels the physiological one, as only pro ducts of reduction or hydrolysis of mitomycin C react with the guanine grou ping of DNA.