Conesa Celia, Pocoví Coloma, Pérez María-Dolores, Calvo Miguel, Sánchez Lourdes
Department of Animal Production and Food Science, Food Technology Unit, Veterinary Faculty, University of Zaragoza, Spain.
Biosci Biotechnol Biochem. 2009 Dec;73(12):2615-20. doi: 10.1271/bbb.90427. Epub 2009 Dec 7.
The possibility of using recombinant human lactoferrin from rice (rhLF) makes it necessary to study its differences from the protein of milk. In this work, the binding of different iron-saturated forms of rhLF to Caco-2 cells was studied. Iron-saturated rhLF bound in higher proportion than the apo-form, but, the data obtained for specific binding were not compatible with receptor-mediated binding. Competition assays showed the same binding capacity for human milk lactoferrin as for rhLF to Caco-2 cells. Another basic protein of milk, lactoperoxidase, was found to compete with rhLF for binding to Caco-2 cell membranes, suggesting an electrostatic interaction. The transport of iron ((59)Fe) bound to rhLF and to citrate and the transport of rhLF ((125)I-labeled) were studied on Caco-2 monolayers. Transport of iron was found to be significantly greater when bound to citrate than to rhLF. The amount of intact lactoferrin that traversed the Caco-2 monolayers was very low, suggesting degradation of it across these cells.
使用来自大米的重组人乳铁蛋白（rhLF）的可能性使得研究其与牛奶中的蛋白质的差异成为必要。在这项工作中，研究了不同铁饱和形式的rhLF与Caco-2细胞的结合情况。铁饱和的rhLF比脱辅基形式的结合比例更高，但是，获得的特异性结合数据与受体介导的结合不相符。竞争试验表明，人乳乳铁蛋白与rhLF对Caco-2细胞具有相同的结合能力。发现牛奶中的另一种碱性蛋白质——乳过氧化物酶，与rhLF竞争结合Caco-2细胞膜，这表明存在静电相互作用。在Caco-2单层细胞上研究了与rhLF和柠檬酸盐结合的铁（（59）Fe）的转运以及rhLF（（125）I标记）的转运。发现铁与柠檬酸盐结合时的转运量明显大于与rhLF结合时的转运量。穿过Caco-2单层细胞的完整乳铁蛋白量非常低，这表明其在这些细胞中发生了降解。
