The mechanism of the interaction between actionmycin D(ACTD) and calf thymus (CT) DNA has been studied by fluorescence method using ethidium bromide (EB) as a fluorescence probe. The results from varied experiments such as fluorescence spectra, fluorescence polarization, Scatchard curve, DNA heat denaturation, and DNA salt effect etc., support that intercalation and groove binding are the two major modes for the interaction ACTD and CT DNA. The absence of the electrostatic binding between the ACTD and the phosphate backbone of CT DNA has been proved.

Key words: ANTICARCINOGEN, DEOXYRIBONUCLEIC ACID, ETHIDIUM BROMIDE, FLUOROSPECTROPHOTOMETRY