Riihimäki Laura, Galkin Anna, Finel Moshe, Heikura Jonna, Valkonen Kaija, Virtanen Vesa, Laaksonen Reijo, Slotte J Peter, Vuorela Pia
Drug Discovery and Development Technology Center, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014 Helsinki, Finland.
Int J Pharm. 2008 Jan 22;347(1-2):1-8. doi: 10.1016/j.ijpharm.2007.06.015. Epub 2007 Jun 19.
Beta-lactoglobulin (betaLG) is a protein that binds ligands like fatty acids and retinol into the hydrophobic pocket. Our purpose was to study bovine and reindeer betaLG as transporter molecules and compare their transport properties across Caco-2 cell membrane. The reindeer betaLG has more valuable binder characteristics than bovine betaLG because it has only one genetic phenotype and it seems to exhibit better immunological properties. The permeation of betaLG in Caco-2 cells was evaluated by immunoblotting, and the permeation of the model substances retinol, palmitic acid and cholesterol with and without betaLG was determined using [(3)H]-labelled ligands. Both bovine and reindeer betaLG were able to pass across a Caco-2 cell monolayer similarly. Unbound and betaLG-bound [(3)H]retinol and [(3)H]palmitic acid were equally transported across the Caco-2 cell layer, whereas [(3)H]cholesterol could not pass across Caco-2 cells with or without betaLG at any of the studied circumstances. Thus, the bovine and reindeer milk betaLG is not a suitable protein to enhance transport of ligands across the Caco-2 cell membrane, used for predicting intestinal absorption.
β-乳球蛋白（βLG）是一种能将脂肪酸和视黄醇等配体结合到疏水口袋中的蛋白质。我们的目的是研究牛和驯鹿的βLG作为转运分子，并比较它们跨Caco-2细胞膜的转运特性。驯鹿βLG比牛βLG具有更有价值的结合特性，因为它只有一种遗传表型，并且似乎表现出更好的免疫特性。通过免疫印迹法评估βLG在Caco-2细胞中的渗透，并使用[³H]标记的配体测定有无βLG时模型物质视黄醇、棕榈酸和胆固醇的渗透情况。牛和驯鹿的βLG都能够以相似的方式穿过Caco-2细胞单层。未结合和与βLG结合的[³H]视黄醇和[³H]棕榈酸在Caco-2细胞层中的转运情况相同，而在任何研究情况下，[³H]胆固醇无论有无βLG都无法穿过Caco-2细胞。因此，牛和驯鹿乳中的βLG不是一种适合增强配体跨Caco-2细胞膜转运的蛋白质，Caco-2细胞膜用于预测肠道吸收。
