Campbell F M, Gordon M J, Dutta-Roy A K
Rowett Research Institute, Aberdeen, Scotland, UK.
Life Sci. 1998;63(4):235-40. doi: 10.1016/s0024-3205(98)00267-7.
To elucidate further the role of placental membrane fatty acid-binding protein (p-FABPpm) in preferential transfer of maternal plasma long chain polyunsaturated fatty acids (LCPUFA) across the human placenta, direct binding of the purified protein with various radiolabelled fatty acids (docosahexaenoic, arachidonic, linoleic and oleic acids) was investigated. Binding of these fatty acids to the protein revealed that p-FABPpm had higher affinities and binding capacities for arachidonic and docosahexaenoic acids compared with linoleic and oleic acids. The apparent binding capacities (Bmax) values for oleic, linoleic, arachidonic and docosahexaenoic acids were 2.0 +/- 0.14, 2.1 +/- 0.17, 3.5 +/- 0.11, 4.0 +/- 0.10 mol per mol of p-FABPpm whereas the apparent dissociation constant (Kd) values were 1.0 +/- .0.07, 0.73 +/- 0.04, 0.45 +/- 0.03 and 0.4 +/- 0.02 microM, respectively (n=3). In the case of human serum albumin, the Kd and Bmax values for all fatty acids were around 1 microM and 5 mol/mol of protein, respectively. These data provide direct evidence for the role of p-FABPpm in preferential sequestration of maternal arachidonic and docosahexaenoic acids by the placenta for transport to the fetus by virtue of its preferential binding of these fatty acids.
为了进一步阐明胎盘膜脂肪酸结合蛋白（p-FABPpm）在母体血浆长链多不饱和脂肪酸（LCPUFA）经人胎盘优先转运中的作用，研究了纯化后的该蛋白与各种放射性标记脂肪酸（二十二碳六烯酸、花生四烯酸、亚油酸和油酸）的直接结合情况。这些脂肪酸与该蛋白的结合情况表明，与亚油酸和油酸相比，p-FABPpm对花生四烯酸和二十二碳六烯酸具有更高的亲和力和结合能力。油酸、亚油酸、花生四烯酸和二十二碳六烯酸的表观结合容量（Bmax）值分别为每摩尔p-FABPpm 2.0±0.14、2.1±0.17、3.5±0.11、4.0±0.10摩尔，而表观解离常数（Kd）值分别为1.0±0.07、0.73±0.04、0.45±0.03和0.4±0.02微摩尔（n = 3）。就人血清白蛋白而言，所有脂肪酸的Kd和Bmax值分别约为1微摩尔和每摩尔蛋白5摩尔。这些数据为p-FABPpm通过优先结合这些脂肪酸在胎盘中优先螯合母体花生四烯酸和二十二碳六烯酸以转运至胎儿这一作用提供了直接证据。
