1994 Volume 17 Issue 7 Pages 970-972
The main aim of this research was to investigate whether conformational alteration of polydeoxyguanylic-polydeoxycytidylic acid (poly [dG-dC]·poly [dG-dC]) by zinc acetate would have an effect on the binding of 1-nitropyrene (1-NP) to poly [dG-dC]·poly [dG-dC]. The binding of 1-NP to poly [dG-dC]·poly [dG-dC] in the hypoxanthine-xanthine oxidase system in vitro was increased by zinc acetate. This increase was abolished when EDTA was added to the preincubated mixture of poly [dG-dC]·poly [dG-dC] and zinc ions. Neither the production of 1-aminopyrene and its expected intermediates, N-hydroxy-1-aminopyrene and 1-nitrosopyrene, nor the 1-NP remaining in the reaction mixture was altered by the addition of zinc acetate without poly [dG-dC]·poly [dG-dC]. From these findings, it seems that the hypoxanthine-xanthine oxidase system is not activated by zinc acetate. On the other hand, under the same reaction conditions but the hypoxanthine-xanthine oxidase system and 1-NP, it has been reported that zinc ions or complexes transform the B-form of poly [dG-dC]·poly [dG-dC] to the Z-form. Therefore, these findings indicate that the formation of the Z-form or intermediates from the B-form by zinc ions may promote the binding of 1-NP to poly [dG-dC]·poly [dG-dC].