Institut für Biologie III der Universität, Schänzlestrasse 1, D-7800, Freiburg i. Br., Federal Republic of Germany.
Planta. 1988 Dec;176(3):343-50. doi: 10.1007/BF00395414.
The affinity of the auxin-transport inhibitor N-1-naphthylphthalamic acid (NPA) for membrane particles as well as for solubilized binding sites from Cucurbita pepo L. hypocotyls was reduced by low concentrations of bisulfite (half-maximal inhibition at 2·10(-3)-3·10(-3) M). Two membrane fractions obtained by sedimentation aided with polyethylene glycol showed differential sensitivity to bisulfite. Other oxidizing or reducing substances tested at 1 mM had no effect, except for N-ethylmaleimide (80% inhibition) and iodine (complete inhibition), both of which reduced the number of binding sites but not their affinity. Addition of bisulfite to either the isoalloxane ring of flavoproteins or to pyridoxal phosphate or quinones is proposed as a possible mechanism of action. Sulfur dioxide, at concentrations measured in polluted air, can lead to bisulfite concentrations in plant tissue sufficient to interfere with NPA-binding sites and hence with auxin transport.
生长素运输抑制剂 N-1-萘基邻苯二甲酰亚胺（NPA）与膜颗粒以及南瓜下胚轴中溶解的结合位点的亲和力，会被低浓度的亚硫酸盐降低（半最大抑制浓度为 2·10(-3)-3·10(-3) M）。用聚乙二醇辅助沉淀获得的两种膜级分对亚硫酸盐表现出不同的敏感性。在 1 mM 下测试的其他氧化或还原物质均无影响，除了 N-乙基马来酰亚胺（80%抑制）和碘（完全抑制），这两者都减少了结合位点的数量，但没有改变其亲和力。亚硫酸盐可能作用于黄素蛋白的异咯嗪环、吡哆醛磷酸或醌上。在污染空气中测量到的二氧化硫浓度，可能会导致植物组织中亚硫酸盐的浓度足以干扰 NPA 结合位点，从而干扰生长素的运输。
