玉米肽亚铁螯合物的结构特性及稳定性

Structural Characteristics and Stability of Corn Peptide-iron Chelates

以玉米肽和氯化亚铁为原料制备玉米肽亚铁螯合物,既能提高玉米肽的利用率,还能为开发铁补剂提供一条新思路。通过紫外光谱和热重分析检测玉米肽亚铁螯合物的结构特性和热稳定性,用分子对接技术对鉴定出的玉米肽段和亚铁离子的结合位点进行模拟,并在不同温度、不同pH值和不同体外消化方式条件下观察玉米肽亚铁螯合物的稳定性。结果表明:紫外吸收峰产生变化,螯合前后特征吸收峰由274.99 nm处移到了275.01 nm,玉米肽和玉米肽亚铁螯合物是两种不同的物质;热重分析显示螯合物和肽的残留率分别为34.94%和18.74%,玉米肽亚铁螯合物的热稳定性相较玉米肽显著提高;FSAASYPDLIDALP、LQQRQQLLNPL和Fe2+的结合能分别为-50.50和-48.61 kJ/mol,提供配位点的是Asp8(天冬氨酸)的氨基,还有Pro7(脯氨酸)、Ser5(丝氨酸)、Tyr6(酪氨酸)、Leu7(亮氨酸)等和亚铁离子形成了疏水作用力;不同温度作用下相对分子质量都集中在1000 u以下,小肽更易螯合和吸收,在pH为中性时较酸碱条件下更稳定。

Corn peptide-iron chelates serve a dual purpose,enhancing the utilization of corn peptides while also offering a novel approach for the development of iron supplements.To examine the structural properties and thermal stability of corn peptide-iron chelates,samples of this compound were prepared from corn peptides and ferrous chloride.Following ultraviolet spectroscopy and thermogravimetric analysis,the binding sites of the identified corn peptide fragments and ferrous ions were simulated by molecular docking.The stability of the corn peptide–iron chelate was observed at different temperatures and pH values,as well as under different in vitro digestion conditions.The results showed that the ultraviolet absorption peak changed.More specifically,the characteristic absorption peak shifted from 274.99 nm to 275.01 nm.Moreover,the corn peptide and corn peptide–iron chelate were compared and found to differ in a number of their properties.Thermogravimetric analysis revealed residual rates of 34.94%and 18.74%for corn chelate and peptide,respectively,while thermal stability of the corn peptide-iron chelate was found to be significantly higher that of the corn peptide.The binding energy levels of FSAASYPDLIDALP and LQQRQQLLNPL with Fe2+were‒50.50 and‒48.61 kJ/mol,respectively,and the amino group of Asp8(aspartic acid)was found to provide the ligand site.In addition,Pro7(proline),Ser5(serine),Tyr6(tyrosine),and Leu7(leucine)were found to bind to the ferrous ions to form hydrophobic interactions.The relative molecular masses were mostly below 1000 u under the action of different temperatures.In addition,small peptides were more easily chelated and absorbed,and were stable under relatively alkaline conditions.