Conroy J M, Roy R G, Vick M A, Salter R D
Mol Immunol. 1983 Jun;20(6):647-53. doi: 10.1016/0161-5890(83)90009-3.
Rabbit antibodies specific for horseradish peroxidase are heterogeneous in their ability to inhibit enzyme activity. Heterogeneity was demonstrated by fractionation of the total antiperoxidase pool by differential ammonium sulfate precipitation and differential elution of antibody from enzyme affinity columns. Both fractionation methods yielded antibody subpopulations that differed in anticatalytic activity. Some antibody subpopulations decreased enzyme activity almost completely at low molar ratios of antibody to peroxidase. Other subpopulations were not effective inhibitors even at great molar excess. Admixture experiments demonstrated that inefficient antibody pools decreased the anticatalytic effect of highly inhibitory antibody. The degree of inhibition observed with unfractionated antiserum is a reflection of the interaction of various antibody subpopulations with the enzyme. No correlation was found between the immunoglobulin class of antiperoxidase and anticatalytic efficiency in analyses of numerous antisera. The determinant specificity of an antiperoxidase molecule determines its anticatalytic ability. A peptide fragment (mol. wt 22,500) of peroxidase prepared by partial tryptic digestion bount 60 to 70% of the total antiperoxidase in a number of antisera. However, the peptide did not bind inhibitory antibodies.
针对辣根过氧化物酶的兔抗体在抑制酶活性的能力上具有异质性。通过硫酸铵分级沉淀对总抗过氧化物酶库进行分级分离，并从酶亲和柱上进行差异洗脱，证明了这种异质性。两种分级分离方法都产生了在抗催化活性方面不同的抗体亚群。一些抗体亚群在抗体与过氧化物酶的低摩尔比下几乎完全降低了酶活性。其他亚群即使在很大的摩尔过量时也不是有效的抑制剂。混合实验表明，低效抗体库降低了高抑制性抗体的抗催化作用。用未分级的抗血清观察到的抑制程度反映了各种抗体亚群与酶的相互作用。在对大量抗血清的分析中，未发现抗过氧化物酶的免疫球蛋白类别与抗催化效率之间存在相关性。抗过氧化物酶分子的决定簇特异性决定了其抗催化能力。通过部分胰蛋白酶消化制备的过氧化物酶的一个肽片段（分子量22,500）结合了许多抗血清中60%至70%的总抗过氧化物酶。然而，该肽不结合抑制性抗体。
