Pruitt K M, Kamau D N, Miller K, Månsson-Rahemtulla B, Rahemtulla F
Department of Biochemistry, School of Dentistry, University of Alabama, Birmingham 35294.
Anal Biochem. 1990 Dec;191(2):278-86. doi: 10.1016/0003-2697(90)90220-4.
Because of the important biological functions of peroxidases, there is growing interest in the measurement of their concentrations in various secretions. At present, there is no standard method which allows for comparisons in reported activities. This report describes procedures which can be used to measure peroxidase enzyme concentrations by commonly employed assays. Regression equations have been determined which can be used to calculate concentrations of bovine lactoperoxidase (LPO), human salivary peroxidase (SPO), and human myeloperoxidase (MPO) from activities measured with the following donors: pyrogallol, guaiacol, 2,2'-azinobis(3-ethylbenzylthiazoline-6-sulfonic acid), and thiocyanate (SCN-). The peroxidation rates of these donors depend upon the concentrations of hydrogen peroxide (H2O2) used in the individual assays and thus, for accurate, reproducible results, these concentrations must be carefully controlled. The SCN- normally present in human saliva will reduce observed reaction rates by simple competition kinetics in the ABTS, guaiacol and pyrogallol assays and will increase the rates observed when Cl- is used as a donor in NBS assay for MPO. Therefore, SCN- must be removed from saliva samples prior to peroxidase activity determination by all assays except the thionitrobenzoic acid (NBS) assay. LPO cannot be used as a standard for either SPO or MPO because the specific activities of LPO, SPO, and MPO are significantly different.
由于过氧化物酶具有重要的生物学功能，人们对测量其在各种分泌物中的浓度越来越感兴趣。目前，尚无能够对所报道的活性进行比较的标准方法。本报告描述了可用于通过常用测定法测量过氧化物酶浓度的程序。已确定回归方程，可根据使用以下供体测得的活性来计算牛乳铁过氧化物酶（LPO）、人唾液过氧化物酶（SPO）和人髓过氧化物酶（MPO）的浓度：邻苯三酚、愈创木酚、2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）和硫氰酸盐（SCN-）。这些供体的过氧化速率取决于各个测定中使用的过氧化氢（H2O2）浓度，因此，为了获得准确、可重复的结果，必须仔细控制这些浓度。人唾液中通常存在的SCN-会在ABTS、愈创木酚和邻苯三酚测定中通过简单的竞争动力学降低观察到的反应速率，并会在MPO的NBS测定中使用Cl-作为供体时增加观察到的速率。因此，除了硫代硝基苯甲酸（NBS）测定外，在通过所有测定法测定过氧化物酶活性之前，必须从唾液样品中去除SCN-。LPO不能用作SPO或MPO的标准，因为LPO、SPO和MPO的比活性有显著差异。
