title: Cooperative binding of fluorescein-labeled clupeine by DNA.
abstract: The alpha-amino group of clupeine fraction Z from herring sperm was coupled with fluorescein. Binding of the labeled protamine by DNA is accompanied by significant fluorescence quenching up to 80%. This allowed the convenient determination of the binding behavior of protamine and DNA. Binding was found to be strongly cooperative and not be significantly affected by the size of DNA. The ionic strength dependence in the range up to 0.3 M NaCl was rather small. Binding parameters were derived according to classical unique-site treatment and to a concept which includes vagrant multi-site binding.
mesh_terms: D001665:Binding Sites; D003026:Clupeine; D004247:DNA; D005452:Fluoresceins; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011479:Protamines; D012965:Sodium Chloride; D013050:Spectrometry, Fluorescence
chemical_list: D005452:Fluoresceins; D011479:Protamines; D012965:Sodium Chloride; D003026:Clupeine; D004247:DNA