Study of binding of some amino acid derivatives of 2,2'-bipyridineplatinun(ii) to calf thymus dna

Abstract

The interactions of glycine, alanine, valine, leucine, proline, methionine, and asparagine derivatives of 2,2'-bipyridineplatinum(II) with calf thymus DNA, polyadenylic acid, and polyguanylic acid have been studied by difference absorption spectral technique. The association constants ( K app) and number of binding sites per 100 nucleotides ( n) have been obtained from binding isotherms which were constructed by treatment of data according to Scatchard equation. The K app values (2.2 × 10 4 to 4.6 × 10 5 M −1) of binding of platinum complexes with DNA are comparable to K app values (5.6 × 10 4 to 2.9 × 10 5 M −1) of binding of platinum complexes with polyguanylic acid. However, the polyadenylic acid does not exhibit any binding to platinum complexes. The hydrogen bonding is, however, the most probable mode of bonding involved in stabilizing the DNA-amino acid complexes.