α-1-抗胰蛋白酶PLowell：一种正常发挥功能但浓度较低的变体。
Alpha-1-antitrypsin PLowell: a normally functioning variant present in low concentration.
作者信息
Cook L, Burdon J, Brenton S, Janus E D, Knight K
机构信息
Department of Chemical Pathology, St Vincent's Hospital, Melbourne, Vic.
出版信息
Aust N Z J Med. 1995 Dec;25(6):695-7. doi: 10.1111/j.1445-5994.1995.tb02855.x.
BACKGROUND
Alpha-1-antitrypsin deficiency is associated with a high risk for the development of emphysema, particularly for phenotype Pi ZZ, which is both deficient and an abnormal inhibitor of the powerful proteolytic enzyme, human neutrophil elastase. The rare variant PLowell is also expressed at abnormally low levels, but its anti-elastase activity has not been described.
AIM
To study the anti-elastase activity of alpha-1-antitrypsin PLowell and compare it to the common M, S and Z proteins.
METHOD
Alpha-1-antitrypsin from a female patient aged 75 years with the rare genotype PLowell NullBellingham was studied for its ability to inhibit human neutrophil elastase in a time dependent manner.
RESULTS
PLowell has near normal function as an inhibitor of human neutrophil elastase with an association rate constant of 7.4 x 10(6) M-1 S-1 at 25 degrees C, similar to that of M and S.
CONCLUSION
Alpha-1-antitrypsin PLowell is associated with a severe deficiency of alpha-1-antitrypsin similar to Z, but unlike that protein it has near normal function as an anti-elastase.
背景
α1抗胰蛋白酶缺乏与肺气肿发生的高风险相关，尤其是对于Pi ZZ表型而言，该表型既缺乏这种物质，又作为强大的蛋白水解酶——人中性粒细胞弹性蛋白酶的异常抑制剂。罕见变体PLowell的表达水平也异常低，但其抗弹性蛋白酶活性尚未见描述。
目的
研究α1抗胰蛋白酶PLowell的抗弹性蛋白酶活性，并将其与常见的M、S和Z蛋白进行比较。
方法
对一名75岁、具有罕见基因型PLowell NullBellingham的女性患者的α1抗胰蛋白酶抑制人中性粒细胞弹性蛋白酶的能力进行了时间依赖性研究。
结果
PLowell作为人中性粒细胞弹性蛋白酶抑制剂的功能接近正常，在25℃时的缔合速率常数为7.4×10⁶M⁻¹s⁻¹，与M和S相似。
结论
α1抗胰蛋白酶PLowell与α1抗胰蛋白酶的严重缺乏相关，类似于Z，但与该蛋白不同的是，它作为抗弹性蛋白酶具有接近正常的功能。
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