RESUMO
The binding site of Fe3+ in the purine base of adenosine 5'-triphosphate (ATP) was studied by nuclear magnetic resonance (NMR). The NMR relaxation rates (R1) of 1H and 31P in ATP solutions free of and containing ferric ions were measured in the pH range of 3-10. It was found that Fe3+ selectively enhanced the relaxation rate of protons. In the presence of Fe3+, the R1 of H2 was much bigger than that of H8 at a lower pH (3-4.5), while at a higher pH (5.5-7.5) the R1 of H8 was more enhanced than H2. At a pH of around 5, both H2 and H8, as well as all three phosphorous, showed a sudden jump in R1. When pH>8, Fe3+ failed to show appreciable enhancement of R1 to all protons and phosphorous. The quantitative data of relaxation rate enhancements suggest that the binding site of Fe3+ in ATP is strongly dependent on pH. At lower pH values, Fe3+ binds N1 but at higher pH it binds to N7. When pH is around 5, the whole purine base donates the aromatic pi-electrons to the ferric ion, forming a ferrocene-like complex, while when pH>8, ATP could not form complexes with Fe3+.
Assuntos
Trifosfato de Adenosina/química , Compostos Férricos/metabolismo , Espectroscopia de Ressonância Magnética , Purinas/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Prótons , Purinas/químicaRESUMO
Sixty chronic active hepatitis patients complicated with hyperbilirubinemia (total bilirubin > 171 mumol/L) were treated with combined treatment of Ganyan IV and Western medicine. The curative effect was compared with that treated with Western medicine alone as control (56 cases). Result showed that the effect of combined therapy group was much better than that of the control in eliminating the jaundice, descending the alanine transaminase (ALT) and improving the reversed A/G ratio (P < 0.05-0.001). In experimental studies, Ganyan IV was applied to the mice with acute liver damage formed by CCl4. It also showed significant effect on reducing total bilirubin and elevating the serum albumin statistically as compared with control (P < 0.05 = 0.01). In addition Ganyan IV could accellerating the bile excretion of normal as well as of liver damaged rats significantly. It was concluded that the Ganyan IV has the effects of treating jaundice, descending transaminase, elevating serum albumin and improving A/G ratio.