Effect of aluminium chloride on binding of 4-hydroxyamino-quinoline 1-oxide to nucleotides

Effect of aluminium chloride on the binding of carcinogenic 4-hydroxyaminoquinoline 1-oxide (4-HAQO) with mouse lung DNA, RNA, and various homopolyribonucleotides was examined in vitro, in the presence of seryl-AMP. Mouse lung DNA, RNA, or homopolyribonucleotide [poly(A), poly(G), poly(I), poly(X), poly(C), or poly(U)] was pretreated with aluminium chloride in an ice bath and the binding with 4-HAQO was examined. Binding with DNA, RNA, poly(A), and poly(G) was markedly inhibited, and their binding rates were 46%, 56%, 53%, and 18% of that of the control, respectively. Binding with poly(C) and poly(U) was hardly different from that of the control. Consequently, effect of aluminium chloride in inhibiting the binding of 4-HAQO with mouse lung DNA and RNA is assumed to be due to the inhibition of its binding with guanine. Effect of various metals (Mg2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Fe3+) on the binding of 4-HAQO with mouse lung DNA was examined and it was found that aluminium chloride had the strongest inhibitory effect, followed by copper and zinc. Trivalent iron showed hardly any inhibition.