A Colorimetric Microassay for the Detection of Agents that Interact with DNA

A simple microtiter assay for the detection of compounds that bind DNA is described. Agents that displace methyl green from DNA are detected spectrophotometrically by a decrease in absorbance at 630 nm. The feasibility of using the assay for detecting DNA-active compounds in fermentation extracts was assessed, and the activities of reference compounds in the methyl green assay and an ethidium bromide displacement method were compared.