title: Dissociation of double-stranded poly(I) . poly(C) by cis-diammine-dichloro-Pt(II).
abstract: The covalent binding of cis-Pt(NH3)2Cl2 on the double stranded poly(I) . poly(C) induced an irreversible dissociation of the two strands. This dissociation was evidenced mainly by poly(I)-Agarose affinity chromatography which allowed to recover free strands of cis-Pt(NH3)2Cl2-poly(I) from a cis-Pt(NH3)2Cl2-poly(I) . poly(C) complex, by density equilibrium centrifugation where free poly(C) could be isolated, and by acid titrations of the metal-poly(I) . poly(C) complexes. The separation of the two strands of the polyribonucleotide upon cis-Pt(NH3)2Cl2 fixation was shown not to exceed 90--95%. A dissociation curve of the polynucleotide double helix as a function of the amount of bound cis-Pt(NH3)2Cl2 was determined and was shown to be of a characteristic cooperative effect. The fixation of the paltinum compound to poly(I) . poly(C) seemed also to be cooperative.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D002945:Cisplatin; D007700:Kinetics; D009690:Nucleic Acid Conformation; D011066:Poly C; D011069:Poly I; D011070:Poly I-C
chemical_list: D011069:Poly I; D011066:Poly C; D011070:Poly I-C; D002945:Cisplatin