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.

中文翻译：

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早产儿胃中随时间释放的乳蛋白衍生肽的肽组学分析。

在牛奶消化的过程中，天然牛奶蛋白酶和婴儿消化蛋白酶将完整的蛋白质破碎成具有潜在生物活性的肽。这项研究调查了在14个早产儿样本中胃消化3小时后肽的释放。通过Orbitrap串联质谱从牛奶和胃样品中提取并分析肽含量。随时间推移以及喂奶添加了牛乳强化剂的婴儿和喂食非强化乳的婴儿之间的相对离子强度（丰度）和肽计数进行了比较。通过与已知生物活性乳肽的序列同源性预测鉴定出的肽的生物活性。在胃消化3小时后，总的和生物活性肽的丰度和计数都持续增加。在考虑了婴儿的体重，身长，在受孕后的年龄，牛奶的强化作用限制了人乳蛋白质中肽的释放。最初释放后在进一步胃消化中存活的肽在结构上比非存活肽更类似于生物活性肽。这项工作是首次提供随着时间的推移在胃消化过程中释放的牛奶肽的全面概况，这是确定哪种肽最有可能与婴儿生物学相关的重要步骤。数据可通过ProteomeXchange获得，其标识符为PXD012192。这项工作是首次提供随着时间的推移在胃消化过程中释放的牛奶肽的全面概况，这是确定哪种肽最有可能与婴儿生物学相关的重要步骤。数据可通过ProteomeXchange获得，其标识符为PXD012192。这项工作是首次提供随着时间的推移在胃消化过程中释放的牛奶肽的全面概况，这是确定哪种肽最有可能与婴儿生物学相关的重要步骤。数据可通过ProteomeXchange获得，其标识符为PXD012192。