Nakazato H, Okamoto T, Nishikoori M, Washio K, Morita N, Haraguchi K, Thompson G A, Okuyama H
Laboratory of Environmental Molecular Biology, Graduate School of Environmental Earth Science, Hokkaido University, Kita-ku, Sapporo 060-0810, Japan.
Plant Physiol. 1998 Nov;118(3):1015-20. doi: 10.1104/pp.118.3.1015.
We recently presented clear evidence that the major low-phosphate-inducible phosphatase of the duckweed Spirodela oligorrhiza is a glycosylphosphatidylinositol (GPI)-anchored protein, and, to our knowledge, is the first described from higher plants (N. Morita, H. Nakazato, H. Okuyama, Y. Kim, G.A. Thompson, Jr. [1996] Biochim Biophys Acta 1290: 53-62). In this report the purified 57-kD phosphatase is shown to be a purple metalloenzyme containing Fe and Mn atoms and having an absorption maximum at 556 nm. The phosphatase activity was only slightly inhibited by tartrate, as expected for a purple acid phosphatase (PAP). Furthermore, the protein cross-reacted with an anti-Arabidopsis PAP antibody on immunoblots. The N-terminal amino acid sequence of the phosphatase was very similar to those of Arabidopsis, red kidney bean (Phaseolus vulgaris), and soybean (Glycine max) PAP. Extracts of S. oligorrhiza plants incubated with the GPI-specific precursor [3H]ethanolamine were treated with antibodies raised against the purified S. oligorrhiza phosphatase. Radioactivity from the resulting immunoprecipitates was specifically associated with a 57-kD band on sodium dodecyl sulfate-polyacrylamide gels. These results, together with previous findings, strongly indicate that the GPI-anchored phosphatase of S. oligorrhiza is a PAP.
我们最近提供了明确的证据，表明浮萍（Spirodela oligorrhiza）中主要的低磷诱导型磷酸酶是一种糖基磷脂酰肌醇（GPI）锚定蛋白，据我们所知，这是高等植物中首次描述的此类蛋白（N. Morita、H. Nakazato、H. Okuyama、Y. Kim、G.A. Thompson, Jr. [1996] Biochim Biophys Acta 1290: 53 - 62）。在本报告中，纯化的57-kD磷酸酶显示为一种紫色金属酶，含有铁和锰原子，在556 nm处有最大吸收峰。正如紫色酸性磷酸酶（PAP）所预期的那样，该磷酸酶活性仅受到酒石酸盐的轻微抑制。此外，在免疫印迹中，该蛋白与抗拟南芥PAP抗体发生交叉反应。该磷酸酶的N端氨基酸序列与拟南芥、红芸豆（Phaseolus vulgaris）和大豆（Glycine max）的PAP非常相似。用GPI特异性前体[3H]乙醇胺孵育的浮萍植株提取物，用针对纯化的浮萍磷酸酶产生的抗体进行处理。所得免疫沉淀物中的放射性与十二烷基硫酸钠 - 聚丙烯酰胺凝胶上的一条57-kD条带特异性相关。这些结果与先前的发现一起，有力地表明浮萍的GPI锚定磷酸酶是一种PAP。
