Protein hydrolysates induce CCK release from enteroendocrine cells and act as partial agonists of the CCK1 receptor
Protein hydrolysates induce CCK release from enteroendocrine cells and act as partial agonists of the CCK1 receptor
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DOI：
10.1021/jf072611h
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发表时间：
2008-02-13
影响因子：
6.1
通讯作者：
Gerhardtt, Cindy C.
中科院分区：
文献类型：
--
作者：
Foltz, Martin;Ansems, Patrick;Gerhardtt, Cindy C.
据报道，蛋白质是所有常量营养素中最令人饱足的。在胃肠道消化时，产生肽，其刺激饱腹感激素如胆囊收缩素（CCK）从肠内分泌细胞释放。因此，生物活性肽可能是具有饱腹作用的功能性食品成分的目标。我们建立了一个体外测定系统，以研究不同的蛋白质水解物是否表现出不同的CCK释放特性。将大豆、豌豆、马铃薯、酪蛋白和乳清蛋白水解物与内源性表达和分泌CCK的肠内分泌细胞系STC-1孵育，通过ELISA测量CCK的释放。所有水解产物在低浓度（>0.1 mg.L-1）下均诱导CCK释放;然而，在不同蛋白水解产物之间没有发现CCK释放特性的显著差异，这表明在STC-1细胞中对水解蛋白的一般的、非特异性的肽敏感机制。由于ELISA对所有具有C-末端CCK八肽但在CCK 1受体（CCK 1 R）上的生物活性不同的CCK同种型表现出灵敏度，因此将第二模块添加到STC-1细胞测定中。在CHO-CCK 1 R细胞中进行细胞内钙测量。将STC-1细胞暴露于蛋白质水解产物后，在CCK 1 R测定中测试培养基。释放的CCK测量具有比ELISA更高的灵敏度和更低的变异性。令人惊讶的是，我们发现一些蛋白质水解产物（大豆>马铃薯>>酪蛋白）也直接刺激CCK 1 R表达细胞，而乳清和豌豆蛋白水解产物是无活性的。由于CCK 1 R在胃肠道中表达，CCK 1 R与膳食肽的直接相互作用可能有助于其饱腹感效应。未来开发用于体重管理的功能性食品生物活性成分的实验可能涉及分离例如大豆蛋白水解物中的活性CCK 1 R激活肽。
Protein has been reported to be the most satiating of all macronutrients. Upon gastrointestinal digestion, peptides are generated that stimulate the release of satiety hormones such as cholecystokinin (CCK) from enteroendocrine cells. As such, bioactive peptides could be the target of Functional Food ingredients with satiating effects. We set up an in vitro assay system to investigate if different protein hydrolysates exhibit varying CCK-releasing properties. Soy, pea, potato, casein, and whey protein hydrolysates were incubated with the enteric endocrine cell line STC-1 that endogenously expresses and secretes CCK Release of CCK was measured by ELISA. All hydrolysates induced CCK release at low concentrations (>0.1 mg.L-1); however, no significant differences in CCK-releasing properties between the different protein hydrolysates were found, suggesting a generic, nonspecific peptide-sensing mechanism in the STC-1 cells on hydrolyzed protein. As the ELISA exhibits sensitivity to all CCK isoforms possessing the C-terminal CCK octapeptide but varying in biological activity at the CCK1 receptor (CCK1R), a secondary module was added to the STC-1 cell assay. Intracellular calcium measurements were performed in CHO-CCK1R cells. Following exposure of the STC-1 cells to the protein hydrolysates, the medium was tested on the CCK1R assay. Released CCK was measured with higher sensitivity and lower variability than in the ELISA. Surprisingly, we found that some protein hydrolysates (soy > potato >> casein) also directly stimulated CCK1R-expressing cells, while whey and pea protein hydrolysates were inactive. As CCK1R is expressed in the GI tract, direct interaction of CCK1R with dietary peptides may contribute to their satiety effects. Future experiments developing bioactive ingredients for Functional Foods for weight management could involve isolation of the active, CCK1R-activating peptides in, for example, soy protein hydrolysates.