Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environment Science, Nanjing Normal University, Nanjing 210097, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Feb;75(2):936-40. doi: 10.1016/j.saa.2009.11.033. Epub 2009 Dec 14.
In order to understand the inhibition mechanism of lanthanum ion (La(3+)) on the activity of horseradish peroxidase (HRP), the effects of La(3+) on the activity, electron transfer and conformation of HRP in vitro were investigated by using cyclic voltammetry (CV), atomic force microscopy (AFM), circular dichroism (CD), high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that La(3+) can combine with the amide groups of the polypeptide chain in HRP molecule, forming the complex of La(3+) and HRP (La-HRP). The formation of the La-HRP complex causes the destruction of the native structure of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure extent of active center, Fe(III) of the porphyrin ring of HRP molecule. Thus, the direct electrochemical and catalytic activities of HRP are decreased. It is a possible inhibition mechanism of La(3+) on the activity of peroxidase.
为了理解镧离子（La（3+））对辣根过氧化物酶（HRP）活性的抑制机制，通过循环伏安法（CV）、原子力显微镜（AFM）、圆二色性（CD）、高效液相色谱（HPLC）、基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF/MS）和电感耦合等离子体质谱（ICP-MS）研究了 La（3+）对 HRP 体外活性、电子转移和构象的影响。结果发现，La（3+）可以与 HRP 分子多肽链上的酰胺基团结合，形成 La（3+）与 HRP 的复合物（La-HRP）。La-HRP 复合物的形成导致 HRP 分子的天然结构被破坏，导致 HRP 分子血红素基团中卟啉环的非平面性降低，进而导致 HRP 分子卟啉环中活性中心的 Fe（III）暴露程度增加。因此，HRP 的直接电化学和催化活性降低。这可能是 La（3+）对过氧化物酶活性抑制的一种机制。
