The binding of diaqua(1,2,2-trimethyl-1,3-cyclopentadiamine)platinum(II) [[Pt(H2O)2(TMCPDA)]2+] to polyriboguanylic acid, polyriboadenylic acid, and polyribocytidylic acid was studied by equilibrium dialysis at pH7 (or pH 5), 37? and ionic strength of 0.1 (0.01 mol.dm-3 phosphate buffer). Using the method of McGhee and von Hippel, the magnitude of the intrinsic binding constant, the degree of cooperativity exhibited in the binding process, and the no. of nucleotide residues bound with each [Pt(H2O)2(TMCPDA)]2+ were obtained. The results are consistent with the results obtained from many studies of the interaction of cisplatin with mononucleoside (or mononucleotide). On the basis of the above results, the binding form of cisplatin with polynucleotide is discussed.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, ANTICARCINOGEN, ATOMIC ABSORPTION SPECTROPHOTOMETRY, PLATINUM COMPLEX, AQUO COMPLEX, CYCLOPENTYL GROUP, CLSPLATINUM, NUCLEOTIDES, PENTANEDIAMINE P, CYTIDYLIC ACID