Majuri R, Gräsbeck R
FEBS Lett. 1986 Apr 7;199(1):80-4. doi: 10.1016/0014-5793(86)81227-3.
Isolated pig liver plasma membranes interact specifically with the haemopexin-haem complex (Kd 4.4 X 10(-7) M). Affinity chromatography was used to isolate a membrane component which binds this complex with high affinity. Pig serum haemopexin was first isolated by affinity chromatography on haemin-Sepharose followed by HPLC gel filtration. Liver membranes solubilized with Triton X-100 were incubated with haemin-Sepharose saturated with haemopexin, and as a control, with affinity gel lacking haemopexin. SDS-poly-acrylamide gel electrophoresis of the eluted protein indicated that from the haemin-Sepharose emerglow-molecular-mass haemin-binding proteins whereas the eluate from haemopexin-haemin-Sepharose contained an additional 71 kDa protein, which did not bind free haemin. This protein appears to represent the haemopexin-haem receptor or a part of it. Haem from the haemopexin complex, as also free haemin, was accepted by a binder in the plasma membrane, which in gel filtration behaved like an 80 kDa molecule. This component probably represents a second functional subunit of the haemopexin-haem receptor.
分离的猪肝质膜与血红素结合蛋白 - 血红素复合物特异性相互作用（解离常数Kd为4.4×10⁻⁷ M）。采用亲和色谱法分离出一种能与该复合物高亲和力结合的膜成分。猪血清血红素结合蛋白首先通过在血红素 - 琼脂糖上进行亲和色谱，然后进行高效液相色谱凝胶过滤进行分离。用Triton X - 100溶解的肝膜与用血红素结合蛋白饱和的血红素 - 琼脂糖一起孵育，作为对照，与缺乏血红素结合蛋白的亲和凝胶一起孵育。对洗脱蛋白进行十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳表明，从血红素 - 琼脂糖中洗脱出低分子量的血红素结合蛋白，而从血红素结合蛋白 - 血红素 - 琼脂糖中洗脱的组分含有一种额外的71 kDa蛋白，该蛋白不结合游离血红素。这种蛋白似乎代表血红素结合蛋白 - 血红素受体或其一部分。来自血红素结合蛋白复合物的血红素以及游离血红素，被质膜中的一种结合剂所接受，该结合剂在凝胶过滤中表现得像一个80 kDa的分子。该组分可能代表血红素结合蛋白 - 血红素受体的第二个功能亚基。
