Boutrou Rachel, Jardin Julien, Blais Anne, Tomé Daniel, Léonil Joëlle
INRA, UMR1253, 65 rue de Saint Brieuc, F-35000 Rennes, France.
J Agric Food Chem. 2008 Sep 10;56(17):8166-73. doi: 10.1021/jf801140d. Epub 2008 Aug 13.
Caseinomacropeptide (CMP) is a peptide obtained from kappa-casein hydrolysis by gastric proteinases and which exhibits various biological activities. The aim of this study was to analyze the intestinal processing of CMP at the brush border membrane (BBM) level. Intestinal BBM vesicles (BBMV) were used to digest glycosylated and unglycosylated CMP. Our results demonstrated that whatever was the glycosylated state of CMP, they were digested by BBMV intestinal enzymes, from macropeptides to free amino acids. The digestion of unglycosylated and glycosylated CMP throughout the action of exopeptidases was similar, but the activity of endopeptideases on glycosylated CMP was limited, certainly due to the attached O-glycosylations. Consequently, much more peptides were identified from the unglycosylated than from the glycosylated CMP. In addition, the glycosylation core as well as the number of the attached glycosylated chain modified the kinetic of digestion; the most heavily glycosylated forms being the slowest digested.
酪蛋白巨肽（CMP）是一种通过胃蛋白酶水解κ-酪蛋白获得的肽，具有多种生物活性。本研究的目的是在刷状缘膜（BBM）水平分析CMP的肠道加工过程。使用肠刷状缘膜囊泡（BBMV）消化糖基化和未糖基化的CMP。我们的结果表明，无论CMP的糖基化状态如何，它们都会被BBMV肠道酶从大肽消化为游离氨基酸。未糖基化和糖基化CMP在外肽酶作用下的消化过程相似，但内肽酶对糖基化CMP的活性有限，这肯定是由于连接的O-糖基化所致。因此，从未糖基化CMP中鉴定出的肽比从糖基化CMP中鉴定出的肽更多。此外，糖基化核心以及连接的糖基化链的数量改变了消化动力学；糖基化程度最高的形式消化最慢。
