In vitro study of DNA interaction with melamine and its related compounds.

In vitro studies on the interactions between native herring sperm DNA (HS-DNA) and melamine as well as its related compounds (MARCs), that is, ammeline, ammelide, and cyanuric acid, have been investigated by spectrophotometric, spectrofluorometric, melting temperature, and viscosimetric techniques. It was found that any of the MARCs might interact with HS-DNA by a groove mode of binding via hydrogen bonds. The interaction constants between any of the MARCs and HS-DNA were at 10⁴-10⁵ L mol⁻¹, determined by both spectrophotometric and spectrofluorometric methods. The thermodynamic studies suggested that the interaction processes were exothermic favored (ΔH < 0) and entropy disfavored (ΔS < 0), which indicated that hydrogen bonds might be the main acting force in the binding of MARCs and DNA.