Das M, Soffer R L
Biochemistry. 1976 Nov 16;15(23):5088-94. doi: 10.1021/bi00668a022.
A method has been developed for quantitating anticatalytic activity in antibody preparations made in goats against pure solubilized angiotensin-converting enzyme from rabbit pulmonary membranes. Anticatalytic activity was purified about 90-fold from a single batch of serum by a procedure including diethylaminoethylcellulose chromatography and elution from Sepharose columns containing covalently bound pure enzyme. Antiholoenzyme antibody was fractionated with respect to charge and binding affinity; however, these different populations each inhibited enzymatic hydrolysis of hippurylhistidylleucine, angiotensin I, and bradykinin. The inhibition dose-response curves were similar for hydrolysis of hippurylhistidylleucine and angiotensin I despite the difference in molecular weight of these substrates. Evidence is presented suggesting that a single molecule of antibody can bind two molecules of enzyme and that at least 18% of the total antiholoenzyme antibody population is directed against determinants which influence catalytic activity. A competitive immunoassay was developed with radioiodinated pulmonary enzyme as displaceable antigen. The anticatalytic and radioimmune assays were used to examine immunological properties of converting enzymes in various rabbit organs and fluids. Kidney, brain, and serum were found to contain converting enzymes which were immunologically identified with that in rabbit lung. Converting enzyme in seminal plasma was similar to the lung enzyme in the anticatalytic assay, but showed lower immunoreactivity in the radioimmune assay.
已开发出一种方法，用于定量山羊制备的抗体制剂中针对兔肺膜中纯溶解的血管紧张素转换酶的抗催化活性。通过包括二乙氨基乙基纤维素色谱法和从含有共价结合的纯酶的琼脂糖柱上洗脱的程序，从一批血清中纯化抗催化活性约90倍。抗全酶抗体根据电荷和结合亲和力进行分级分离；然而，这些不同的群体均抑制了马尿酸酰组氨酸亮氨酸、血管紧张素I和缓激肽的酶促水解。尽管这些底物的分子量不同，但马尿酸酰组氨酸亮氨酸和血管紧张素I水解的抑制剂量-反应曲线相似。有证据表明，单个抗体分子可以结合两个酶分子，并且至少18%的总抗全酶抗体群体针对影响催化活性的决定簇。开发了一种以放射性碘化肺酶作为可置换抗原的竞争性免疫测定法。抗催化和放射免疫测定法用于检查各种兔器官和体液中转换酶的免疫学特性。发现肾脏、大脑和血清中含有与兔肺中的转换酶具有免疫学相关性的转换酶。精浆中的转换酶在抗催化测定中与肺酶相似，但在放射免疫测定中显示出较低的免疫反应性。
