The influence of N-7 platination and methylation on the stability of deoxyguanosine and deoxyguanylyl-(3'-5')-deoxyguanosine.
The rates of degradation of N-7 platinated deoxyguanosine (dG) and deoxyguanylyl-(3'-5')-deoxyguanosine (dGpdG) were followed in 66 mM Tris-HCl (pH 7.4) at 100 degrees C. The half-life for the intramolecular cross-link of cis-diamminedichloroplatinum(II) (cis-Pt) between two neighboring guanines (Pt-dGpdG) was 86 min, and the half-life of the intermolecular cross-link of cis-Pt on two guanines (dG-Pt-dG) was 54 min. For comparison the half-lives of dGpdG and the N-7 methylated dGpdG (Me-dGpdG) were 636 min and 11 min, respectively. The end product of the degradation of dGpdG, Pt-dGpdG and dG-Pt-dG was guanine, while Me-dGpdG was degraded to 7-methylguanine. In the case of dG-Pt-dG the main reaction pathway was through the depurination of one of the deoxyguanosines; in the case of Pt-dGpdG the degradation occurred either through the cleavage of one of the N-glycosidic bonds or through the cleavage of one of the Pt-bonds.
Försti
A
A
Institute of Occupational Health, Helsinki, Finland.
Vodicka
P
P
Hemminki
K
K
D002851:Chromatography, High Pressure Liquid; D003849:Deoxyguanosine; D015226:Dinucleoside Phosphates; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008745:Methylation; D010984:Platinum
D015226:Dinucleoside Phosphates; C034298:deoxyguanylyl-(3'-5')-guanosine; D010984:Platinum; D003849:Deoxyguanosine