Interaction of anthracycline antibiotics with biopolymers. VIII. Binding parameters of aclacinomycin A to DNA.

The binding of aclacinomycin A to DNA was investigated spectrophotometrically under equilibrium conditions. The self-association behaviour of aclacinomycin A was identified as dimerization. Based on a model of overlapping potential binding sites the subsequent results were obtained: equilibrium constant of cooperative binding K = (7.58 +/- 2.15) X 10(6) M(-1), size of a binding site alpha = 3.98 +/- 0.14 base pairs, cooperativity parameter sigma = 0.12 +/- 0.10. These parameters were compared with those of adriamycin, daunomycin, and iremycin to draw some conclusions regarding the structural specialities of aclacinomycin A.