Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), Madrid, Spain.
Istituto di Scienze dell'Alimentazione-Consiglio Nazionale delle Ricerche, Avellino, Italy.
Food Res Int. 2022 Jul;157:111238. doi: 10.1016/j.foodres.2022.111238. Epub 2022 Apr 9.
The use of enzymes from the brush border membrane (BBM) in simulated gastrointestinal digestion of milk proteins has been evaluated. With this purpose, the resistant sequences from casein and milk whey proteins after INFOGEST in vitro digestion with and without BBM have been analyzed by tandem mass spectrometry. The use of BBM revealed additional cleavages to those found with pancreatic enzymes, although the number of total identified peptides decreased due to the reduction of the peptide size. These new cleavages were mainly attributed to the activity of amino- and carboxy-peptidases, which was also reflected in the higher concentration of free amino acids found in the gastrointestinal digests with BBM. The peptidome of the simulated gastrointestinal digests was compared with that previously obtained in digests aspirated from human jejunum after oral administration of the same substrates. The addition of BBM did not change significantly the peptide profile, although it allowed the identification of peptides found in human digests. However, none of the models was able to reproduce the large variety of peptides found in vivo. In addition, in vitro transepithelial transport of six β-casein derived peptides resistant to gastrointestinal digestion, including the opioid β-casomorphin-7, was also evaluated. The results point to the importance of the nature of the N- and C-terminal end for the transport rate through the Caco-2 cell monolayer. Therefore, the use of BBM as a supplementary step after simulated pancreatic digestion can be considered in bioavailability studies since the final sequence can determine the absorption of peptides.
已经评估了在模拟胃肠道消化中使用来自刷状缘膜（BBM）的酶来消化牛奶蛋白。为此，通过串联质谱分析了 INFOGEST 体外消化有和没有 BBM 时乳清蛋白和酪蛋白的抗性序列。使用 BBM 显示出比使用胰酶消化时更多的裂解，尽管由于肽大小的减小，鉴定出的总肽数量减少。这些新的裂解主要归因于氨基肽酶和羧基肽酶的活性，这也反映在胃肠道消化中发现的游离氨基酸浓度更高。将模拟胃肠道消化的肽组与先前在口服相同底物后从人空肠抽吸的消化物中获得的肽组进行比较。添加 BBM 并没有显著改变肽谱，尽管它允许鉴定在人消化物中发现的肽。然而，没有一种模型能够复制体内发现的大量肽。此外，还评估了六种β-酪蛋白衍生肽对胃肠道消化的抗性的体外跨上皮转运，包括阿片样β-酪啡肽-7。结果表明，对于通过 Caco-2 细胞单层的转运速率，N-和 C-末端的性质很重要。因此，在模拟胰酶消化后作为补充步骤使用 BBM 可以考虑用于生物利用度研究，因为最终序列可以决定肽的吸收。
