Gilvocarcins, new antitumor antibiotics. 4. Mode of action

The mode of action of gilvocarcins was studied. Gilvocarcins V, M and A possessed antibacterial activities decreasing in that order. Gilvocarcin V inhibited DNA synthesis in Bacillus subtilis through strong interaction with DNA and resulting cleavage. Gilvocarcin M showed interaction with DNA and a small change in DNA mobility upon electrophoresis in agarose gel, while gilvocarcin A showed no interaction with DNA, thus reflecting their relative biological activities.