サイズ排除高速液体クロマトグラフィー/誘導結合プラズマ質量分析法による植物中カドミウム-γグルタミルシステイニルペプチド複合体の状態分析

抄録

Size exclusion high-performance liquid chromatography/inductively coupled plasma mass spectrometry (SE-HPLC/ICP-MS) was employed for the speciation of cadmium-(γ-glutamylcysteinyl peptide)(CP-γEC peptide)complexes from hydroponically grown komatsuna, a kind of Chinese mustard(Brassica campestris L. ), and rice(Oryza sativa L. cv koshihikari)plants exposed to Cd. In the SE-HPLC/ICP-MS chromatogram, the Cd-γEC peptide complexes from komatsuna and rice exposed to 50 μM CdCl_2 gave broad peaks compared with that of horse kidney metallothionein, especially in the rice plant, which indicated that the size of the Cd-γEC peptide complexes was heterogeneous. From the retention time in the SE-HPLC/ICP-MS chromatogram, molecular weights of the Cd-γEC peptide complexes were estimated to distribute centering on 10000 and 6000 for komatsuna and rice, respectivelty. Reversed-phase HPLC analysis revealed that the structure of the γEC peptide was different between komatsuna and rice. In komatsuna, elevation of Cd stress intensity(0.1〜10μM)resulted in an increase in the Cd-γEC peptide complex content in the plant, and the molecular weight distribution in low stress(0.1μM)was not identical with that in high stress (1 and 10μM).