KINETIC-STUDY OF DNA-BINDING OF CISPLATIN AND OF A BICYCLOALKYL-SUBSTITUTED (ETHYLENEDIAMINE) DICHLOROPLATINUM(II) COMPLEX

Salmon sperm DNA platination has been conducted under strictly pseudo- first-order conditions with cisplatin (1) and rac-{(1S,2S,4S)-exo-2-(a minomethyl)-2- amino-7-bicyclo[2.2.1] heptane}dichloroplatinum(II) (2) . An aquation step first occurs for both com plexes, with the rate con stants k(1) = 1.12(0.02) x 10(-4) s(-1) and 1.47(0.02) x 10(-4) s(-1) respectively for 1 and 2 at 37 degrees C, values in agreement with tho se previously reported. It is followed by the actual platination step whose second-order rate constant has been determined for the first tim e by physicochemical techniques. The values for 1 and 2 respectively a re: k(2) = 2.08(0.07) M-1 s(-1) and 3.9(0.4) M-1 s(-1). These kinetic data are discussed in the context of a comparison of several biologica l properties of the two complexes.