Mitomycin And Porfiromycin - These compounds are produced by various species of Streptomyces, and are powerful antimitotic agents. Because they cause the death of both microbial and mammalian cells, their use is confined to anticancer therapy. Heating of dsDNA ruptures the H bonds linking the base pairs, and the two strands are separated (denaturation). Recovery (renaturation) of bacterial and viral DNA occurs if the Cooling is slow. It does not take place if cooling is rapid, because correct alignment of complementary base pairs does not take place.
However, if the DNA is treated with mitomycin or mitomycin like compounds, renaturation takes place even during rapid cooling. Mito mycin cross links hold the two DNA strands together during heating, and permit renaturation on rapid cooling. The antimitotic affects of DNA depend upon the fact that DNA synthesis stops whenever the replication fork reaches the mitomycin molecule cross link.
