竹红菌甲素锌、镁络合物某些光敏性质的研究

THE STUDIES ON SEVERAL PHOTOSENSITIZING CHARACTERISTICS OF HA AND ITS COMPLEXES WITH MAGNESIUM AND ZINC IONS

本文主要对竹红菌甲素的锌和镁离子络合物的原初光敏反应和自敏氧化能力进行分析,并与未络合的竹红菌甲素做了比较。实验证实:甲素经络合后的吸收光谱分别在628nm(镁)和620nm(锌)出现一新吸收峰,与此同时,原540um和580um的吸收峰下降或消失。研究证明络合后的活性氧(包括单线态氮,超氧阴离子自由基)产率下降,下降幅度随着金属离子的比例增加而增加。深入研究证明活性氧产率下降的原因是电子传递受到阻碍。镁和锌络合物自氧化速率分别比甲素大8.2倍和3.0倍。

Several properties, including absorption spectraactiveoxygen pro-duction and the rate of autooxidation of HA and its complexes with magnesium andzinc ions, were investigated and compared in this paper. New absorption peaks at 620nm (Zn) and 628 nm (Mg) appeared in HA-Zn and HA-Mg complex solutions res-pectively, while the original peaks at 540 nm and 580 nm in HA solution reduced, oreven though disappeared at higher molecular ratio of metal ion to HA. These pheno-mena suggested that the intra-hydrogen bond between carbonyl and hydroxyl groupsof HA were replaced by bivalent cations. ESR data indicated that efficiency of bothsinglet oxygen and superoxide anion radical reduced significantly in the solution ofHA complexes compared with that of HA. A simple test we designed proved the directelectron transfering from semiquinone radical of HA to oxygen. However, the forma-tion of semiquinone radical of HA was inhibited by magnesium of zinc ions and thenresulted in reduction of superoxide anion radicals. The rate constants of autooxidationof HA-Mg and HA-Zn complexes were 8.2 and 3.0 times bigger than that of HA.