[Effect of DNA-tropic antineoplastic and antiparasitic agents on DNAase I activity]

Kinetics of DNAase I activity was studied in reaction mixtures containing tightly bound to DNA drugs used for study and treatment of cancer and some other diseases. Distamycin proved to be the strongest inhibitor. The inhibitory activity of the substances studied decreased as follows: distamycin greater than or equal to actinomycin D greater than or equal to ethidium bromide > proflavine > carminomycin > bleomycin. The latter substance did not possess any inhibitory action. The data obtained are discussed in relation to mechanisms of interaction of the substances studied and DNA. High efficiency was typical for substances, which were bound with the DNA molecules on their small curvature.