植物蛋白源肽促进钙吸收的生物学功效及其机制的研究

Recent studies show that different sources of plant protein structure and physiological activity are very different, but the release of the peptide with the same physiological activity by proteolysis. We found in preliminary studies, the hydrolysis of soybean protein soybean peptide combines with calcium to form in mice peptide calcium complex to promote calcium absorption, calcium-binding soy peptide containing "EEEQ-E, EE-QQQ、EDEDE", such as glutamyl acid and aspartic acid linked in sequence. Peanut, sunflower and soy proteins are important plant proteins. It is unclear whether calcium-binding peptides released from the peanut and sunflower proteins by enzymatic hydrolysis promote calcium absorption via the formation of peptide-calcium compounds. This report describes the construction of a novel model of peptide-calcium binding to define potential mechanisms of plant-derived peptide-calcium binding. We then explored the influence of peptide-calcium compounds on calcium absorption rates and bone quality in rats to define the biological efficacy of their effects on calcium absorption. The relationship between peptide-calcium compounds and intestinal cellular calcium absorption was explored to identify the mechanism by which calcium absorption is promoted by plant-derived peptides and to clarify the nutritional pathways through which such compounds act.

研究表明，不同来源的植物蛋白质结构和生理活性虽然有很大差异，但是通过酶水解可释放出相同生理活性的肽。申请者在前期研究中发现，用酶水解大豆蛋白获得的肽与钙离子结合形成可溶性的肽钙复合物，该复合物能促进大鼠的钙吸收，其结构特点是肽链中均含有"EEEQ-E、EE-QQQ、EDEDE"等序列。花生蛋白、葵花籽蛋白与大豆蛋白同样也是重要的植物蛋白资源，那么花生蛋白和葵花籽蛋白是否也能通过酶水解后释放出能与钙结合的肽，形成的肽钙复合物能否促进钙吸收等问题尚不明确，值得深入探讨。为此，本课题首先构建花生肽、葵花籽肽与钙的结合模型，明确植物蛋白源肽与钙结合的机制；探测花生肽、葵花籽肽与钙结合形成的复合物对大鼠钙吸收率和骨质量的影响，明确其促进钙吸收的生物学功效；考察花生肽钙复合物、葵花籽肽钙复合物与肠道细胞钙吸收的关系，揭示植物源肽促进钙吸收的机制，阐明植物源肽在促进机体钙吸收方面的营养品质和利用途径。

研究表明，不同来源的植物蛋白质结构和生理活性虽然有很大差异，但通过酶水解可释放出相同生理活性的肽。申请者在前期研究中发现，用酶水解大豆蛋白获得的肽与钙离子结合形成可溶性的肽钙复合物，该复合物能促进大鼠的钙吸收。花生蛋白、葵花籽蛋白与大豆蛋白同样也是重要的植物蛋白资源，那么花生蛋白和葵花籽蛋白是否也能通过酶水解释放出能与钙结合的肽，形成的肽钙复合物能否促进钙吸收等问题尚不明确，值得深入探讨。为此，1、本课题首先研究了能与钙结合的花生肽、葵花籽肽的结构，鉴定出7种钙结合葵花籽肽：①FVTPEEEQQQMHQR；②LAGGISSEHIQGQQQFQGQQGR；③LDTQNHENOLDENQRR；④FLAGNPQAQAQSQQQQQR；⑤GGIGIGGYGTTGHHGL；⑥NDRNQEVVAIIVDDVNNPANQLDFQAK；⑦QYGGQQTQTVER。鉴定出8种钙结合花生肽：①LLGFGINAENNHR；②VIQQGQATVTVANGNNR；③NESEEEGAIVTVRGGLR；④IVQNLRGENESEEQGAIVTVK；⑤TNNNDNQLDQFPRR；⑥LEENAGGEQEERGQRRR；⑦FQGQDQSQQQQDSHQKVHR；⑧ FEGEDQSQQQQQDSHQKVR。2、选择葵花籽肽FVTPEEEQQQMHQR和花生肽 IVQNLRGENESEEQGAIVTVK化学合成并分析其钙结合量，发现合成的花生肽和葵花籽肽的确能与钙结合且均具有较高的钙结合量；3、研究了葵花籽肽-钙复合物、花生肽-钙复合物促进钙吸收的生物学功效，发现其均能促进生长期小鼠的钙吸收，并增强其骨质量和骨密度，效果优于碳酸钙，与CPPPs-Ca相当；4、进一步采用Caco-2单层细胞模型，研究葵花籽肽-钙复合物、花生肽-钙复合物促进肠道细胞钙转运的效果，发现其均具有促进肠道细胞钙转运吸收的能力，效果显著优于CaCl2，与CPPs-Ca相当。