Tischner R, Ward M R, Huffaker R C
Pharmaphysiologisches Institut, Universität Göttingen, Federal Republic of Germany.
Planta. 1989;178:19-24.
Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.
抗硝酸还原酶（NR）免疫球蛋白-G（IgG）片段抑制了小球藻细胞对硝酸盐的摄取，但对硝酸盐吸收没有影响。完整的抗NR血清和免疫前IgG片段对硝酸盐摄取没有影响。通过双水相分配分离的质膜（PM）组分中检测到了与膜相关的NR。在500 mM NaCl和1 mM乙二胺四乙酸中对PM囊泡进行超声处理，并未去除与PM相关的NR，该NR占小球藻总NR活性的比例高达0.8%。PM NR可被 Triton X-100溶解，并被小球藻NR抗血清灭活。质膜NR存在于完全缺乏可溶性NR活性的铵培养小球藻细胞中。通过十二烷基硫酸钠电泳和蛋白质印迹法测定，PM和可溶性NR的亚基大小分别为60 kDa和95 kDa。
