Nutrition Program, School of Biological and Population Health Sciences, College of Public Health and Human Sciences , Oregon State University , Corvallis , Oregon 97331 , United States.
Department of Pediatrics , University of California, Davis , Sacramento , California 95817 , United States.
J Proteome Res. 2019 Mar 1;18(3):912-922. doi: 10.1021/acs.jproteome.8b00604. Epub 2019 Jan 24.
Over the course of milk digestion, native milk proteases and infant digestive proteases fragment intact proteins into peptides with potential bioactivity. This study investigated the release of peptides over 3 h of gastric digestion in 14 preterm infant sample sets. The peptide content was extracted and analyzed from milk and gastric samples via Orbitrap tandem mass spectrometry. The relative ion intensity (abundance) and count of peptides in each sample were compared over time and between infants fed milk fortified with bovine milk fortifier and infants fed unfortified milk. Bioactivity of the identified peptides was predicted by sequence homology to known bioactive milk peptides. Both total and bioactive peptide abundance and count continuously increased over 3 h of gastric digestion. After accounting for infant weight, length, and postconceptual age, fortification of milk limited the release of peptides from human milk proteins. Peptides that survived further gastric digestion after their initial release were structurally more similar to bioactive peptides than nonsurviving peptides. This work is the first to provide a comprehensive profile of milk peptides released during gastric digestion over time, which is an essential step in determining which peptides are most likely to be biologically relevant in the infant. Data are available via ProteomeXchange with identifier PXD012192.
在牛奶消化过程中，天然牛奶蛋白酶和婴儿消化蛋白酶将完整的蛋白质片段化为具有潜在生物活性的肽。本研究在 14 个早产儿样本组中研究了胃消化 3 小时内肽的释放情况。通过轨道阱串联质谱法从牛奶和胃样本中提取和分析肽含量。比较了每个样本中随时间和经牛奶奶粉强化喂养的婴儿与未经强化喂养的婴儿之间的肽的相对离子强度（丰度）和计数。通过序列同源性预测鉴定出的肽的生物活性，已知生物活性的牛奶肽。在胃消化 3 小时内，总肽和生物活性肽的丰度和计数均持续增加。在考虑婴儿体重、长度和胎龄后，牛奶的强化限制了人乳蛋白释放的肽。与初始释放后存活下来的肽相比，存活下来的肽在结构上与生物活性肽更相似。这是首次提供随时间推移在胃消化过程中释放的牛奶肽的综合概况，这是确定哪些肽在婴儿中最有可能具有生物学相关性的重要步骤。数据可通过 ProteomeXchange 以标识符 PXD012192 获得。
