Characterisation of polyphenol-protein interactions using the apple allergen Mal d 1 as an example

多酚（PP），亲水性次生植物代谢物，与许多健康促进作用有关，例如心脏保护作用。这一来自流行病学研究的结论已经在体外和干预研究中进行了多年的调查。PP通常与细胞壁成分、蛋白质和/或脂质结合在一起发生。然而，为了减少复杂性，大多数研究都是在没有或尽量减少大分子基质成分影响的情况下进行的，例如通过果汁的管理。然而，PP与基质的相互作用会影响PP的稳定性、溶解度和生物可及性。此外，PP能够不可逆地改变蛋白质结构。这可能会导致营养价值下降，或者，正如对花生和苹果的初步研究表明，这些食物的致敏性降低。聚丙烯具有很大的结构多样性，因此它们的化学性质差异很大，这对它们与大分子基质的相互作用起着决定性的作用。这种结构-效应关系尚未得到全面的研究。不存在pp -基质在体内和体外相互作用稳定性的详细知识，以及相关的影响因素和反应条件。在本项目中，以苹果过敏原Mal d1为例，对PP与蛋白质的相互作用进行了彻底的研究，并选择了苹果中发现的PP。到目前为止，还没有发现苹果品种的致敏性与其Mal - 1含量之间有显著的相关性。然而，由于过敏患者所描述的耐受性良好的品种通常具有较高的PP含量，因此可以假设PP与Mal d1之间的相互作用在降低致敏电位中起重要作用。本项目的目的是研究PP结构对PP- mal - 1相互作用的机制、强度和动力学的影响。目的是用标准方法确定致敏性和低致敏性苹果品种之间的具体差异，如定性和定量的PP组成、氧化酶的活性以及内源性氧化抑制剂的浓度。在简化模型系统中研究了分离PP与r-Mal d1之间的相互作用。低聚PP结构（当苹果被切开时形成）与Mal d1的相互作用也令人感兴趣。PP相互作用对Mal d 1构象的影响（被认为是致敏潜力的重要标准）及其在口服消化条件下的稳定性，通过圆二色性和FT-IR光谱进行了评估。在此背景下建立的研究PP-Mal d1相互作用的方法可转移到进一步的pp -蛋白相互作用中。

Polyphenols (PP), hydrophilic secondary plant metabolites, are associated with a number health promoting effects e.g. cardioprotective effects. This conclusion from epidemiological studies has been investigated in vitro and by intervention studies for years. PP always occur in plants in combination with cell wall components, proteins and/ or lipids. How-ever, in order to reduce complexity, most studies are performed without or minimizing the influence of macromolecular matrix components, e.g. by the administration of juices. Nevertheless, the inter-action of PP with the matrix influences the stability, solubility and bioaccessibility of PP. In addition, PP are able to irreversibly alter protein structures. This might lead to a decreased nutritional value or, as initial studies on peanuts and apples indicate, a reduction of the allergenic potential of these foods. PP are characterized by a large structural diversity and, therefore, differ significantly in their chemical properties, which plays a decisive role for the interaction with macromolecular matrices. This structure-effect relationship has not yet been investigated comprehensively. Detailed knowledge of the stability of PP-matrix interaction in vivo and in vitro, as well as the relevant impact factors and reaction conditions, do not exist. In this project, PP-protein interactions are examined thoroughly using the apple allergen Mal d 1 as an example and selected PP found in apples. So far, no significant correlation has been found between the allergenicity of an apple variety and its Mal d 1 content. However, since the varieties described by allergy sufferers as well tolerated usually exhibit high PP contents, it is assumed that the interaction between PP and the Mal d1 plays an important role in reducing the allergenic poten-tial. The aim of this project is to investigate the impact of the PP structure on mechanism, strength and kinetics of the PP-Mal d 1 interaction. It is intended to determine specific differences among allergenic and hypoallergenic apple varieties e.g. the qualitative and quantitative PP composition, the activity of oxidizing enzymes as well as the concentration of endogenous oxidation inhibitors using standard methods. The interaction between isolated PP and r-Mal d 1 is studied in simplified model systems. The interaction of the oligomeric PP structures (formed when apples are cut) with Mal d 1 is also of interest.The effect of PP interaction on the Mal d 1 conformation, which is assumed to be an important criterion for the allergenic potential, and its stability under oral digestion conditions, are assessed by circular dichroism and FT-IR spectroscopy. The methods established in this context, investigating the PP-Mal d 1 interaction, are transferable to further PP-protein interactions.