METAL ION-COORDINATING PROPERTIES OF 2'-DEOXYGUANOSINE 5'-MONOPHOSPHATE (DGMP(2-))(1) IN AQUEOUS-SOLUTION - QUANTIFICATION OF MACROCHELATE FORMATION

The stability constants of the 1:1 complexes formed between Mg2+, Cu2, or Zn2+ (= M2+) and dGMP(2-), i.e., M(H;dGMP)(+) and M(dGMP), were d etermined by potentiometric pH titration in aqueous solution. It is sh own that in all three M(dGMP) complexes the phosphate-coordinated M2interacts also to a certain degree with N7 of the nucleobase. The form ation degree of the resulting macrochelates varies between 41 +/- 7% f or Mg(dGMP) and 93 +/- 1% for Cu(dGMP). The connected increased comple x stabilities for M(dGMP) are somewhat larger than those for M(GMP).