Horseradish peroxidase/hydrogen peroxide-catalyzed oxidation of the carcinogen N-hydroxy-N-acetyl-2-aminofluorene as effected by cyanide and ascorbate.
Horseradish peroxidase and H2O2 mediate N-hydroxy-N-acetyl-2-aminofluorene (N-OH-AAF) conversion into two more potent carcinogens, 2-nitrosofluorene and N-acetoxy-N-acetyl-2-aminofluorene. Optical studies of this system indicate that horseradish peroxidase is operating as a peroxidase with N-OH-AAF as the electron donor. Our studies confirm the earlier finding that 2-nitrosofluorene and N-acetoxy-N-acetyl-2-aminofluorene are the products of the type II enzyme-mediated oxidation of N-OH-AAF, but surprisingly, the results with the type VI enzyme indicate that more 2-nitrosofluorene was formed and, in addition, another product absorbing at 245 nm was formed. If ascorbate is present in the N-OH-AAF/horseradish peroxidase/H2O2 system, ascorbate is oxidized preferentially. Cyanide, a known inhibitor of the peroxidase, does not inhibit when N-OH-AAF is the electron donor. The reaction products are the same in the presence or absence of cyanide.
D000099:Acetoxyacetylaminofluorene; D001205:Ascorbic Acid; D055598:Chemical Phenomena; D002621:Chemistry; D003486:Cyanides; D005449:Fluorenes; D006735:Horseradish Peroxidase; D006861:Hydrogen Peroxide; D006881:Hydroxyacetylaminofluorene; D066298:In Vitro Techniques; D009603:Nitroso Compounds; D010084:Oxidation-Reduction; D010544:Peroxidases; D013056:Spectrophotometry, Ultraviolet
D003486:Cyanides; D005449:Fluorenes; D009603:Nitroso Compounds; C012458:2-nitrosofluorene; D006881:Hydroxyacetylaminofluorene; D000099:Acetoxyacetylaminofluorene; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D010544:Peroxidases; D001205:Ascorbic Acid