THE CHIRALITY SELECTIVITY IN THE UPTAKE OF PLATINUM(II) COMPLEXES WITH 1,2-CYCLOHEXANEDIAMINE ISOMERS AS CARRIER LIGAND BY HUMAN ERYTHROCYTES

The uptake kinetics of cisplatin analogs of 1,2-cyclohexanediamine (da ch) isomers with various leaving groups, by human erythrocytes in plas ma isotonic buffer, were studied, The experimental results showed that the uptake rate constants (k values) decrease with the change of leav ing group in the sequence: chloride (Cl) > squaric acid (SA)> oxalate (OX)> demethylcantharic acid (DA), with the same dach isomer as carrie r group, It is noteworthy that for the platinum (II) complexes with th e same leaving group, the k values always reduce as: 1R, 2R-dach > 1R, 2S-dach > 1S, 2S-dach, This result reflects the chirality selectivity , No differences in reactivity to protein thiols and effects on membra ne permeability were found for the R,R-, R,S-, S,S-isomeric complexes, It is proposed that the chirality selectivity in uptake is due to the recognition of the chirality of the platinum complexes by the erythro cyte membrane. The interactions between the chiral platinum complexes and the head groups of the membrane phospholipid molecules are probabl y involved.