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蛋白质在体内主要是以二肽 (dipeptide)形式被吸收 ,其转运和摄取过程依赖肠上皮细胞刷状缘的二肽载体(dipeptidetransporter ,PepT1)。PepT1相对分子质量为 12 70 0 0 ,共有 70 8个氨基酸残基 ,12个跨膜域 ,PepT1不但可转运二肽和三肽 ,而且对一些重要的类二肽药物 (如 β 内酰胺类抗生素和血管紧张素转换酶抑制剂等 )也可通过PepT1吸收。因此 ,二肽载体在蛋白质的吸收、临床营养支持和药物吸收方面具有十分重要的生物学功能。Caco 2细胞是人结肠癌上皮细胞 ,其结构和生化作用都类似于人小肠上皮细胞 ,PepT1在Caco 2细胞上常规表达 ,常采用该细胞模型研究PepT1的生物学功能
Proteins are mainly digested in the body and are dependent on the dipeptide transporter (PepT1) on the brush border of intestinal epithelial cells during transport and uptake. PepT1 has a relative molecular mass of 127000 and contains 708 amino acid residues and 12 transmembrane domains. PepT1 not only transports dipeptides and tripeptides, but also plays an important role in some important dipeptide drugs such as beta-lactam antibiotics And angiotensin-converting enzyme inhibitors, etc.) can also be absorbed by PepT1. Therefore, the dipeptide vectors have very important biological functions in terms of protein absorption, clinical nutritional support and drug absorption. Caco 2 cells are human colon epithelial cells, whose structure and biochemical function are similar to that of human intestinal epithelial cells. PepT1 is routinely expressed on Caco 2 cells. This cell model is often used to study the biological functions of PepT1