Chinese Journal of Rice Science

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Existence of Ca2+/H+ Antiporter and Its Properties in the Plasma Membranes of Rice Roots

SHEN Guo-ming   

  • Received:1900-01-01 Revised:1900-01-01 Online:2005-07-10 Published:2005-07-10

水稻根质膜Ca2+/H+反向转运体的存在及其特性

沈国明   

  1. 浙江省台州学院 生物系, 浙江 临海 317000; E-mail:gmshen@tzc.edu.cn

Abstract: The peptide-sepcific antipobies of the Ca2+/H+ antiporter clearly reacted with a 44.5 kD protein from rice root plasma membrane by immunoblotting. Ca2+ transport activities of rice root plasma membrane by the filtration method using 45Ca2+, indicated that there was a Ca2+/H+ antiporter(OsCAX2) depended on transmembrane proton gradient in the rice root plasma membrane, and manganese ion could restrain Ca2+ transport activities of OsCAX2 partially. Kinetics analysis showed that the Vmax of OsCAX2 was 34.72 nmol/(min·mg), the Km was 3.83 μmol/L and the optimum pH value was 7.2.

Key words: Ca2+/H+ antiporter, rice, root, plasma membrane

摘要: 由Ca2+/H+反向转运体蛋白的特异多肽制备的抗体,通过免疫印迹显示水稻根质膜上存在分子量为44.5 kD的蛋白。同位素闪烁记数法检测水稻根质膜上45Ca2+转运活性显示存在依赖于跨膜质子梯度的Ca2+/H+反向转运体,Mn2+可部分地抑制其转运活性。动力学分析表明,OsCAX2的Vmax=34.72 nmol/(min·mg), Km=3.83 μmol/L,其最适pH为7.2。

关键词: Ca2+/H+反向转运体, 水稻, 根, 质膜