DNA: Reaction with Chloroquine

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Science  03 Sep 1965:
Vol. 149, Issue 3688, pp. 1111-1113
DOI: 10.1126/science.149.3688.1111


Diflerence spectrophotometry shows that double-stranded DNA produces mnarked changes in the absorption spectrum of chloroquine; only minor changes occur with single-stranded DNA. A DNA-chloroquine complex was demonstrated to sediment in the analytical ultracentrifuge. Chloroquine strongly elevated the thermal dissociation temperature, Tm, of DNA. It is concluded that the drug forms a complex with DNA by ionic interaction and stabilizes the helix.