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目的研究汞对人类胎盘碱性磷酸酶（ＰＬＡＰ）活力及其荧光光谱的影响，以探讨汞对ＰＬＡＰ抑制的分子机制。②方法应用分光光度法测定不同浓度ＨｇＣｌ２存在下的酶活力，用荧光法检测其荧光光谱；用双倒数作图法确定ＨｇＣｌ２对该酶的抑制类型。③结果当ＨｇＣｌ２浓度为０．２５ｍｍｏｌ／Ｌ时，酶活力及其荧光强度迅速下降，最大发射峰位由３４７ｎｍ蓝移至３４０ｎｍ；ＨｇＣｌ２浓度为０．２５～１．００ｍｍｏｌ／Ｌ时，酶活力、荧光强度及峰位均无显著变化；当ＨｇＣｌ２浓度＞１．００ｍｍｏｌ／Ｌ时，随其浓度增加，酶活力和荧光强度又快速下降，但峰位不变；ＨｇＣｌ２浓度高达１０．００ｍｍｏｌ／Ｌ时，酶仍有部分活力。ＨｇＣｌ２是ＰＬＡＰ混合性抑制剂，其抑制常数为３．６０ｍｍｏｌ／Ｌ．④结论ＨｇＣｌ２抑制了ＰＬＡＰ的活力，并使其构象发生了改变。
Objective To study the effect of mercury on human placental alkaline phosphatase (PLAP) activity and its fluorescence spectrum to explore the molecular mechanism of mercury inhibition of PLAP. Methods The enzymatic activities of HgCl2 in the presence of different concentrations of HgCl2 were determined by spectrophotometry. Fluorescence was used to detect the fluorescence spectra. The double-counting plot was used to determine the inhibitory effect of HgCl2 on this enzyme. Results When the concentration of HgCl2 was 0.25mmol / L, the enzyme activity and fluorescence intensity decreased rapidly, and the maximum emission peak shifted from 347nm to 340nm. When the concentration of HgCl2 was 0.25-1.00mmol / L, When the concentration of HgCl 2> 1.00mmol / L, the enzyme activity and fluorescence intensity decreased rapidly with the increase of HgCl 2 concentration, but the peak position remained unchanged. When HgCl 2 concentration was as high as 10.00mmol / L , The enzyme still has some vitality. HgCl2 is a PLAP mixed inhibitor with an inhibitory constant of 3.60 mmol / L. ④ Conclusion HgCl2 inhibits the activity of PLAP and conformational changes.