Lund J, Nordlund L, Gustafsson J A
Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital, Sweden.
Biochemistry. 1988 Oct 4;27(20):7895-901. doi: 10.1021/bi00420a047.
A binding protein for certain methyl sulfone metabolites of polychlorinated biphenyls (PCB) was partially purified from lung cytosol of untreated female rats. The protein has an Mr of 13,000 and a pI of 5.3 in the absence of reducing agents. In the presence of dithioerythreitol or beta-mercaptoethanol, the protein is split into subunits with a more basic pI. The 13-kDa protein was electroeluted from SDS-polyacrylamide gels, and an antiserum against the protein was raised in rabbit. The immunoglobulin fraction was shown to contain monospecific antibodies against the 13-kDa protein as determined by Western immunoblots. The antibodies retained partially purified binding protein labeled with radioactive ligand when subjected to protein A-Sepharose chromatography and caused a shift in the elution of the labeled protein from Sephadex G-75 and a shift in its sedimentation behavior on sucrose gradients. Due to striking similarities in physicochemical characteristics of the 13-kDa protein and a protein purified from rabbit lung and uterus, uteroglobin, the anti 13-kDa protein antibodies were tested for cross-reactivity. As judged by Western immunoblots, the anti 13-kDa protein antibodies did not cross-react with uteroglobin and the two proteins, although similar, do not seem to be identical. The 13-kDa protein is proposed to be responsible for the accumulation of certain methylsulfonyl-PCBs in lung tissue of rats. Monospecific antibodies against the 13-kDa protein should constitute immunochemical probes of great value in attempts to elucidate the physiological role of the protein as well as its possible role in PCB-induced respiratory toxicity.
从未处理的雌性大鼠肺胞质溶胶中部分纯化出一种针对多氯联苯（PCB）某些甲基砜代谢物的结合蛋白。在没有还原剂的情况下，该蛋白的相对分子质量为13,000，等电点为5.3。在二硫赤藓糖醇或β-巯基乙醇存在的情况下，该蛋白会分裂成等电点更偏碱性的亚基。将13 kDa的蛋白从SDS-聚丙烯酰胺凝胶中电洗脱出来，并在兔体内制备针对该蛋白的抗血清。通过蛋白质免疫印迹法测定，免疫球蛋白组分显示含有针对13 kDa蛋白的单特异性抗体。当进行蛋白A-琼脂糖凝胶层析时，这些抗体保留了用放射性配体标记的部分纯化结合蛋白，并导致标记蛋白在Sephadex G-75上的洗脱峰发生位移，以及其在蔗糖梯度上的沉降行为发生变化。由于13 kDa蛋白与从兔肺和子宫中纯化出的一种蛋白——子宫珠蛋白在物理化学特性上有显著相似性，因此对13 kDa蛋白抗体进行了交叉反应性测试。根据蛋白质免疫印迹法判断，13 kDa蛋白抗体与子宫珠蛋白不发生交叉反应，这两种蛋白虽然相似，但似乎并不相同。有人提出13 kDa蛋白负责大鼠肺组织中某些甲基磺酰基多氯联苯的蓄积。针对13 kDa蛋白的单特异性抗体在试图阐明该蛋白的生理作用及其在多氯联苯诱导的呼吸道毒性中可能发挥的作用时，应构成具有重要价值的免疫化学探针。
