“…The quantum yield increases by more than 50 between the bound and unbound form. A large number of thermodynamic and spectroscopic studies have been performed on the DNA-DAPI complex (Kapuscinski & Szer, 1979;Masotti et al, 1981Masotti et al, , 1982Manzini et al, 1983Manzini et al, , 1985aWilson et al, 1985aWilson et al, , 1989Szabo et al, 1986;Barcellona et al, 1986;Kubista et al, 1987). It is known that, in addition to binding to AT sites, DAPI can also bind to GC pairs, although with less affinity and without fluorescence enhancement.…”