Nucleic Acids Research, 1982, Vol. 10, No. 24 8211-8223
© 1982
CHEMISTRY |
On the cooperative and noncooperative binding of ethidium to DNA

Department of Chemistry, University of Rochester Rochester, NY 14627, USA
*To whom correspondence and reprint requests should be addressed.
Received July 14, 1982. Revised September 9, 1982. Accepted September 28, 1982.
The equilibrium binding of ethidium bromide to native DNAs and to poly(dG-dc).poly(dG-dC) has been studied by both phase partition and direct spectrophometric techniques. The binding isotherms obtained from both experimental techniques show that ethidium binds in a cooperative manner to E.coli DNA. on the other hand, no evidence of coperative binding was observed in the binding isotherms obtained with calf thymus,C. perfringens, M.Lysodeikticus, or poly(dG-dC).(dG-dC) under the experimental conditions used (0.1 M Nacl).
Present address: Department of Chemistry, Busch Campus, Rutgers University, The State University, The State University of New Jersey, New Brunswick, New Jersey 08903