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膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)（Cholinesterase，ChE）是一(yi)類(lei)催化(hua)酰(xian)(xian)基(ji)(ji)膽(dan)(dan)(dan)(dan)堿(jian)水解(jie)的酶(mei)類(lei)，又稱酰(xian)(xian)基(ji)(ji)膽(dan)(dan)(dan)(dan)堿(jian)水解(jie)酶(mei)。根(gen)據底物特異性和(he)抑制劑敏感性不同(tong)，可將其(qi)分為兩類(lei)，一(yi)類(lei)是乙(yi)酰(xian)(xian)膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)（AchE，EC 3.1.1.7，又稱真性膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)，特異性膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)），負責(ze)水解(jie)乙(yi)酰(xian)(xian)膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)；另一(yi)類(lei)是丁酰(xian)(xian)膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)（BchE，EC 3.1.1.8，又稱血清膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)，假性膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)，非特異性膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)酶(mei)），負責(ze)水解(jie)分子(zi)量(liang)較大的芳(fang)基(ji)(ji)或烷基(ji)(ji)膽(dan)(dan)(dan)(dan)堿(jian)酯(zhi)(zhi)，如(ru)丁酰(xian)(xian)膽(dan)(dan)(dan)(dan)堿(jian)和(he)苯甲酰(xian)(xian)膽(dan)(dan)(dan)(dan)堿(jian)。

 分布與生理功能 

乙酰(xian)(xian)膽(dan)堿(jian)酯(zhi)酶(mei)由神(shen)(shen)經(jing)(jing)細胞(bao)和骨髓新生紅(hong)細胞(bao)合成，主要分布于腦灰質、神(shen)(shen)經(jing)(jing)節內(nei)的(de)神(shen)(shen)經(jing)(jing)細胞(bao)和神(shen)(shen)經(jing)(jing)肌(ji)肉(rou)接頭等神(shen)(shen)經(jing)(jing)組織中，在(zai)紅(hong)細胞(bao)、血(xue)清等非(fei)神(shen)(shen)經(jing)(jing)組織中也有分布。乙酰(xian)(xian)膽(dan)堿(jian)酯(zhi)酶(mei)的(de)主要生理功能是高效水解神(shen)(shen)經(jing)(jing)末梢釋放的(de)乙酰(xian)(xian)膽(dan)堿(jian)，保證(zheng)神(shen)(shen)經(jing)(jing)沖(chong)動(dong)在(zai)突觸間(jian)的(de)正常傳導。

丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)由肝臟粗面內(nei)質網合(he)成(cheng)，廣泛分(fen)布于(yu)血清中，在(zai)肝臟、肺臟、脾臟等組織(zhi)中也(ye)有分(fen)布。丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)半衰期約為10d，較白蛋白半衰期21d短，可靈敏反映肝細胞蛋白質合(he)成(cheng)能(neng)力的(de)變化，因此其(qi)活(huo)性是(shi)臨床(chuang)診(zhen)斷肝病(bing)(bing)的(de)重要生物指標之一。丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)的(de)異常過表達與阿爾茨海默病(bing)(bing)高(gao)度相關，該病(bing)(bing)患(huan)(huan)者血清中丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)活(huo)性明顯高(gao)于(yu)正常水(shui)平，而丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)抑制劑可有效(xiao)緩解患(huan)(huan)者癥狀。丁酰(xian)膽堿(jian)(jian)酯(zhi)(zhi)(zhi)(zhi)酶(mei)能(neng)夠與有機磷及氨基甲酸酯(zhi)(zhi)(zhi)(zhi)類農藥結(jie)合(he)，清除其(qi)對(dui)生物體的(de)毒害(hai)作用。

檢測原理

乙酰膽(dan)(dan)(dan)堿(jian)(jian)酯酶(mei)(mei)水解膽(dan)(dan)(dan)堿(jian)(jian)酯類的(de)(de)速度為(wei)：乙酰膽(dan)(dan)(dan)堿(jian)(jian)＞丙(bing)酰膽(dan)(dan)(dan)堿(jian)(jian)＞丁(ding)酰膽(dan)(dan)(dan)堿(jian)(jian)，有(you)研究表明(ming)，使用乙酰膽(dan)(dan)(dan)堿(jian)(jian)作(zuo)(zuo)為(wei)底(di)物(wu)(wu)測(ce)得的(de)(de)乙酰膽(dan)(dan)(dan)堿(jian)(jian)酯酶(mei)(mei)活性是使用丁(ding)酰膽(dan)(dan)(dan)堿(jian)(jian)作(zuo)(zuo)為(wei)底(di)物(wu)(wu)測(ce)得活性的(de)(de)30~100倍。因此，可使用乙酰膽(dan)(dan)(dan)堿(jian)(jian)作(zuo)(zuo)為(wei)底(di)物(wu)(wu)檢(jian)測(ce)乙酰膽(dan)(dan)(dan)堿(jian)(jian)酯酶(mei)(mei)活性，使用丁(ding)酰膽(dan)(dan)(dan)堿(jian)(jian)作(zuo)(zuo)為(wei)底(di)物(wu)(wu)檢(jian)測(ce)丁(ding)酰膽(dan)(dan)(dan)堿(jian)(jian)酯酶(mei)(mei)活性。

乙酰(xian)膽(dan)堿(jian)酯酶(mei)催化乙酰(xian)膽(dan)堿(jian)水(shui)解(jie)生(sheng)(sheng)成(cheng)膽(dan)堿(jian)，丁酰(xian)膽(dan)堿(jian)酯酶(mei)催化丁酰(xian)膽(dan)堿(jian)水(shui)解(jie)生(sheng)(sheng)成(cheng)膽(dan)堿(jian)，膽(dan)堿(jian)與(yu)二硫對硝基(ji)苯(ben)甲酸（DTNB）作用生(sheng)(sheng)成(cheng)5-巰基(ji)-硝基(ji)苯(ben)甲酸（TNB）；TNB在412nm處有吸收峰，通過測定412nm吸光度增加速率，計算兩種酶(mei)的活性。

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