Bio-activity of Phytate-Metal Complexes and Its Regulation of Hydrolysis Enzyme Phytase

阐明了金属-植酸配合物的结构与性质的关系，表明金属-植酸配合物的特殊性质在生物体系中是有用的。(1)植酸盐与金属离子的相互作用用pH滴定法测定了各种金属植酸盐的稳定常数，并给出了结构和光谱信息。这表明磷酸基团之间的氢键的重要性，这也决定了金属配位位点。(2)植酸酶活性的金属离子依赖性尼日尔曲霉植酸酶被认为是植酸盐活性生物分子受体的模型。该酶的反应速率受不同金属离子的影响，这些金属离子有助于在pH 6下形成植酸盐的反应底物，金属-植酸盐-H5。在这里，我们展示了金属离子的新方面，植酸酶的底物是一种金属络合物。(3)植酸金属配合物的生物活性Li ^+对植酸酶反应的抑制作用以及与植酸金属配合物的强相互作用表明Li^+的抗抑郁活性可能与其作用有关。通过对人KB细胞的生长抑制作用，研究了不同金属-植酸配合物的抗癌作用。所有金属体系，特别是Ca^<2+>，对植酸酶的催化活性均高于植酸盐~（12）Na，表明植酸钙配合物是一种真正的活性物种，为植酸盐和植酸酶在医药上的应用奠定了基础。

We made the structure-property relations for metal-phytate complexes clear and showed that the specific properties of metal-phytate complexes is usefully available in biological system.(1) Interactions of phytate with metal ionsStability constants of various metal-phytate species were evaluated by pH titrations and were able to give the structural information as well as the spectra. These showed the importance of hydrogen bond between the phosphate group which also determines the metal coordination site.(2) Metal ions dependence of enzyme phytase activityEnzyme phytase from Aspergillus niger is considered to be a model of active bio-molecular receptor of phytate. This enzyme reaction rate were varied by various metal ions which assist the formation of reactive substrate of phytate at pH 6, Metal-phytate-H5. Here we demonstrated new aspect of the metal ion that the substrate of phytase is a metal complex.(3) Bio-activity of Metal-phytate complexLi^+ inhibition of phytase reaction and strong interaction of Li-phytate complex indicated possible relationship with the antidepressant activityof Li^+. Anti-cancer effect of various metal-phytate complexes were studied by growth inhibition of human KB cell. All metal system, especially Ca^<2+>, were more effective than phytate 12Na and this indicated Ca-phytate complex as a true active species.These results obtained here were served a base for application of phytate and phytase to medical drugs.