Study On The Interaction Of Functional Complexes With Amino Acids, Nucleotides And Nucleic Acids

Study on interaction of 23 kinds of amino acids, peptides and their analogues with trans-[en2Os(η2-H2)(CF3SO3)](CF3SO3) at different pD values. Experimentsshow that in acidic condition, the carboxyl group in amino acids can coordinate with Os(Ⅱ), and there exist H-D coupling of the dihydrogen of the Os complex with D2O in strongly acidic condition, N does not coordinate with Os(Ⅱ); In alkaline condition, the carboxyl group can coordinate with Os, and the coordinating species have trans and cis isomers, and the trans isomer can convert to cis with time; N of - NH2-in aaaaaaaaa -amino group can coordinate with Os(Ⅱ) while that in γ-Amino-n-Butyric Acid can not do that. Since the target of some anti tumor agents are nucleic acids and proteins, we demonstrate a competitive mode to study how anti tumor complex Me2SnCl2 binds to amino acid Ala, and the minimum binding amount of the metal anti tumor metal complexes binding with amino acid is also obtained.Study on the binding site and binding amount of a number of antirumor metal complexes, cisplatin, Cp2TiCl2 and (CH3)2SnCl2, to target molecule mononucleotides dGMP in aqueous solution, by virtue of a 1H NMR recognition probe,trans-[en2Os(η2-H2)(CF3SO3)](CF3SO3) in a competitive mode. And the minimumbinding percentages of antitumor metal complexes to different sites of dGMP were also obtained. In our experiment we found that cisplatin and Cp2TiCl2 mainly bind to base N of mononucleotides, while Me2SnCl2 mostly binds to phosphate oxygen, which is in accordance with the previous results.Systematically study on the cleavage mechanism of Mg-dien complex acting on nucleotides: Determining of the pseudo first order cleavage rate constants on different pH values by agarose gel electrophoresis; By virtue of 1H NMR and 31P NMR, exploring the action mechanism of Mg-dien with 5'-dAMP, 3'-dAMP, plenty of experimental data indicate that Mg-dien can cleave the phosphate-oxygen bond in the sugar ring of the mononucleotide, releasing inorganic phosphate oxygen. Which show DNA cleavage mediated by Mg-dien occurs via a hydrolytic path. Mg-dien isthe simplest Mg complex that can hydrolyze DNA reported so far, the study on its action mechanism is in favor of our understanding natural enzyme's action mode. It is worth mentioning that the cleavage experiments were carried out under conditions of excess substrate (25 fold) over catalyst (Mg-dien), and do represent a true "enzyme-like" reaction.The oxidation of Na4Fe(CN)6 complex by S2O82- anion was found to follow an outer-sphere electron transfer mechanism. We firstly carried out the reaction at pH = 1. The specific rate constants of the reaction, kox, are (8.1±0.07) ×10-2 and (4.3±0.1) ×10-2M-1sec-1 at μ=1.0 M NaClO4, T = 25℃ for pH = 1(0.1 M HClO4) and 8, respectively. The activation parameters, obtained by measuring the rate constants of oxidation at T = 10-30℃, were △H≠= (69.0±5.6) kJ.mol-1, △S≠= (-0.34±0.041) ×102 J.mol-1.K-1 for pH= 1and △H≠= (41.315.5) kJ.mol-1, △S≠= (-1.27±0.33)×102 J.mol-1 .K -1 for pH= 8,respectively. The cyclic voltammetry of Fe(CN)63-/4- shows that the oxidation is a one-electron reversible redox process with E1/2 values of 0.55 and 0.46 V vs. normal hydrogen electrode(NHE) at μ=1.0 M LiClO4, for pH=1 and pH =8 (Tris), respectively. The kinetic results were discussed on the basis of Marcus theory, and the conclusion that the oxidation of Fe(CN)64-complex, like the others, has occurred in the non-adiabatic regime has been drawn.