硫化氢过硫化调节机制下葱属多硫化物提高粮食铁锌生物利用率机理研究

Among the signaling mechanisms invoked for H2S, cysteine sulfydryl or polysulfide persulfidation is the one that is most commonly cited. A variety of active sulphide in Allium plants, which could be under the action of H2S to release a kind of novel active sulfur type of hydropersulfides. We have managed to prepare a variety of sulfides in Allium. The previous investigation showed that the crude extract from garlic bulbs could have a reaction with the solution containing H2S leading to the changing of ultraviolet absorption. With the addition of extract could change the biological available state of iron and zinc present in grain and legume food. In the project, the mechanisms of sulfides in Allium for improving bioavailability of food iron and zinc underlying the persulfidation of H2S would be explored to find a novel active sulphur as mineral nutritional fortification substance. First, analysis from the degree of nutriology, the bioaccessibility of iron and zinc was estimated using the method in vitro to simulate gastrointestinal digestion. Second, analysis from the degree of chemistry, thermodynamic information and chemical kinetics of a reaction about binding events would be determined with ITC and the stopped-flow technology, respectively. Third, analysis from the degree of biology, the founction of GSR, GGT and Alliinase involved in metal-binding would be discussed. Finally, the mechanisms of Allium sulfides for improving bioavailability of food iron and zinc underlying the persulfidation of H2S would be concluded.

H2S对活性巯基及多硫化物的过硫化修饰作用是其行使氧化还原信号传导的主要机制，葱属作物中含有多种活性巯基及多硫化物，可以在H2S的过硫化作用下产生新的活性硫种类氢过硫化物。我们已能熟练制备多种葱属硫化物，前期探索中发现大蒜硫化物粗提液可以与含有H2S的储备液发生作用导致紫外最大吸收波长的改变，说明有新物质生成，将其添加到大豆中能明显提高铁锌的存在状态。本项目将在H2S过硫化机制下研究葱属硫化物对提高粮食铁锌生物利用率的影响，以期发现一类新的活性硫类作为矿质元素强化剂。本项目拟从营养学角度利用已建立的模拟胃肠消化模型检测铁锌可利用状态的变化，从化学角度利用等温滴定量热技术、动力学停留技术测定铁锌螯合热力学和动力学参数，从生化角度考察γ-谷氨酰转肽酶、蒜酶、谷胱甘肽还原酶在过硫化机制下的作用。进而提出在H2S过硫化机制下葱属硫化物提高铁锌生物利用率机理。

H2S对活性巯基及多硫化物的过硫化修饰作用是其行使氧化还原信号传导的主要机制，葱属作物中含有多种活性巯基及多硫化物，可以在H2S的过硫化作用下产生新的活性硫种类氢过硫化物。本项目在探索葱属硫化物提高粮食铁锌生物利用率过程中发现添加巯基类物质如GSH可以显著增强效果，并且大蒜硫化物与H2S储备液能发生作用导致紫外吸收变化，说明有新物质生成，因此，在H2S的作用机制下能很好的阐述大蒜硫化物提高铁锌生物利用率的机理。目前，硫烷化修饰或者说产生蛋白过硫化物是H2S参与蛋白调节的主要机制，被认为是一种进化保守的翻译后修饰作用，是H2S有益的生物调节作用。然而，还有问题需要揭示，H2S是如何在还原状态下完成硫烷化作用的，以及这个过程中GSH和DTT有何作用。项目中以5种酶为研究对象，包括蒜酶、L和D-乳酸脱氢酶、乙醇脱氢酶、葡萄糖-6-磷酸脱氢酶，探索了H2S和巯基物GSH、DTT与酶蛋白的作用机制，揭示出GSH和DTT与蛋白作用机制与H2S硫烷化机制截然不同，是一种α-碳亲核进攻或者硫与巯基交换的脱硫烷机制，并且放出副产物H2S。项目中对H2S的硫烷化机制和GSH的脱硫烷化机制做了详细阐述，并以此得到活性巯基物质GSH、DTT添加到葱属硫化物中提高粮食铁锌生物利用率的机理。

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