烟酰胺腺嘌呤二核苷酸磷酸与纳米氧化铝和勃姆石的作用(英文)

Interactions of Nicotinamide Adenine Dinucleotide Phosphate with Nano-Boehmite and Nano-Corundum

采用多种现代分析手段研究了烟酰胺腺嘌呤二核苷酸磷酸(NADP+)与纳米氧化铝(γ-Al2O3)和纳米勃姆石(γ-AlOOH)的相互作用,结果显示NADP+与γ-AlOOH主要通过静电作用相结合,而在γ-Al2O3表面除了静电和氢键作用外,还存在通过铝与磷酸根中的氧配位形成的内层配合物;在3<pH<5时,NADP+的最大吸附量明显下降,这可能是由于酸性条件下溶解Al髥的竞争吸附所致;NADP+与2种纳米铝化合物的吸附过程均为自发的,且符合Langmuir等温式。荧光结果表明吸附后NADP+折叠式构象增加,由此可能影响依赖于NADP+的脱氢酶体系的生物活性。

The adsorption behavior of NADP＋ on the nano-boehmite （T-AlOOH） and nano-corundum （T-Al2O3） surfaces was examined using batch adsorption experiments over a broad range of NADP^＋ concentrations and pH values. The results indicate that NADP＋ is predominantly adsorbed on the boehmite surface as an outer-sphere by electrostatic interaction via NADP^＋ phosphate and surface hydroxyl groups over the investigated pH values. In contrast, on the corundum surface, two outer-sphere complexes are formed by the electrostatic force and the hydrogen bond in all cases, and another minor inner-sphere complex involving the phosphate is formed at low pH values. However, at 3〈pH〈5, the extent of NADP＋ adsorption falls significantly below the expected value. This can be interpreted in terms of competitive adsorption of dissolved AI（III） with NADP＋ under acidic conditions. Moreover, the adsorption behavior on the two nano-aluminum compounds could be well fitted with the ideal Langmuir isotherms and both of them are spontaneous. The adsorption might influence the activity of NADP^＋- specific dehydrogenase in the biological system.