title: A spectrophotometric study on the interaction of neutral red with double-stranded DNA in large excess.
abstract: With the measurement of molecular absorption, the interaction of neutral red (NR) with double-stranded DNA in large excess was investigated. It was found that the interaction of NR, existing in the acidic state (HNR) at pH 4.56, with double-stranded structure DNA displays different spectral features depending on the molar ratio of HNR/DNA, R. If R>1.33, the binding process is characterized by a binding constant at the 10(6) level with each nucleotide residue of double-stranded DNA binding one HNR molecule. If R<0.67, the binding constant is reduced to the 10(4) level, and the binding number for each nucleotide residue of double-stranded DNA to HNR is less than one.
authors.affiliation: Institute of Environmental Chemistry, Southwest Normal University, Chongqing 400715, People's Republic of China.
authors.forename: C Z
authors.initials: CZ
authors.lastname: Huang
authors.forename: Y F
authors.initials: YF
authors.lastname: Li
authors.forename: P
authors.initials: P
authors.lastname: Feng