Presence of aspartic dipeptides with β peptide bond and/or D-aspartyl residue in rat blood after ingestion of porcine liver protein hydrolysate
Presence of aspartic dipeptides with β peptide bond and/or D-aspartyl residue in rat blood after ingestion of porcine liver protein hydrolysate
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摄入猪肝蛋白水解物后，大鼠血液中存在具有 β 肽键和/或 D-天冬氨酸残基的天冬氨酸二肽
DOI：
10.31989/bchd.v2i7.619
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Kenji Sato
中科院分区：
文献类型：
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作者：
A. Ejima;Kotaro Yamada;Kenji Sato
动物实验表明，口服猪肝蛋白水解物（LPH）可以改善酒精诱导的肝脏毒性，以及运动和豆豆蛋白a诱导的小鼠低运动活性。产生有益作用的肽尚未被确定。最近，在摄入其他食物蛋白水解物后，在人类血液中发现了食物来源的肽。这些肽是脯氨酸、羟脯氨酸或焦谷氨酰二肽和三肽，可以抵抗外肽酶消化。其中一些肽在体内和体外都发挥着重要的生物学作用，这与摄入后的生物反应有关。本研究的目的是鉴定食用LPH后大鼠血液中的食源性肽。结果：在体外外肽酶消化中，鉴定出焦谷氨酰、脯氨酸、羟脯氨酸和天冬氨酸二肽。通过LC-MS/MS分析，天冬氨酸肽（Asp-Val、Asp-Ile、Asp-Leu和Asp-Phe）呈现多个峰，表明存在异构体。在每个序列中存在4个具有L-和d -天冬氨酸残基的异构体，以及α和β肽键。给药后，大鼠血浆中具有β肽键和/或d -天冬氨酸残基的特殊天冬氨酸二肽的数量显著增加，而其他常见天冬氨酸二肽的数量无显著增加。结论：多肽中的天冬氨酸残基外消旋和异构化发生在LPH制备或消化过程中。罕见的天冬氨酸肽具有开展多种生物活性的潜力。关键词：肽，水解蛋白，天冬氨酸，异肽，生物利用度，d -氨基酸
Background: Animal experiments have demonstrated that oral administration of a porcine liver protein hydrolysate (LPH) ameliorates alcohol-induced liver toxicity, as well as exercise- and concanavalin A-induced low locomotor activity in mice. The peptides responsible for the beneficial effect have not yet been identified. Recently, presence of food-derived peptides in human blood has been detected post ingestion of other food protein hydrolysates. These peptides are prolyl, hydroxyprolyl, or pyroglutamyl di- and tri-peptides, and resist exopeptidase digestion. Some of these peptides exert significant biological roles in vitro and in vivo, which have been associated with the biological response post ingestion. The objective of the present study was to identify the food-derived peptides in rat blood after ingestion of LPH.Results: In the in vitro exopeptidase digest of LPH, pyroglutamyl, prolyl, hydroxyprolyl, and aspartic dipeptides were identified. The aspartic peptides (Asp-Val, Asp-Ile, Asp-Leu, and Asp-Phe) showed multiple peaks by LC-MS/MS, indicating the presence of isomers. Four isomers with L- and D-aspartyl residues, and α and β peptide bonds were present in each sequence. After administration of LPH, the amounts of unusual aspartic dipeptides with β peptide bond and/or D-aspartyl residue significantly increased in rat plasma, while those of the other usual aspartic peptides did not.Conclusions: Racemization and isomerization of aspartyl residues in peptides occur during the preparation of LPH or following its digestion. The unusual aspartic peptides have a potential for carrying out diverse biological activities.Key words: Peptide, food protein hydrolysate, aspartic, isopeptide, bioavailability, D-amino acid