Deleide G, Donà V, Malvano R
Clin Chim Acta. 1979 Dec 17;99(3):195-201. doi: 10.1016/0009-8981(79)90262-6.
The effects of the enzyme-hapten chemical bridge on the quality of the enzymatic tracer in homogeneous enzymoimmunoassay were studied, using as a model the conjugates of glucose-6-phosphate dehydrogenase with different phenobarbital and diphenylhydantoin carboxyalkyl derivatives. For both series of conjugates the maximal immunoinhibition level was found to depend critically on the bridge length, best results being obtained with carboxymethyl derivatives. A tendency to immuno re-activation with increasing degrees of hapten substitution in the enzyme structure, particularly evident for phenobarbital-carboxyethyl and carboxypropyl conjugates, was also observed. Effects of steric hindrance on the antibody interaction, in the case of short bridges, and ineffectiveness of antibody interaction towards the active enzyme site, in the case of long bridges, have been hypothesized to contribute in defining a critical bridge size for immuno inhibition processes. Instead the tendency to immunoactivation has been tentatively interpreted in terms of occurrence of "conformational" antibody interactions involving hapten residues in enzyme regions other than the catalytic site.
以葡萄糖-6-磷酸脱氢酶与不同苯巴比妥和二苯乙内酰脲羧烷基衍生物的结合物为模型，研究了酶-半抗原化学桥对均相酶免疫分析中酶标记物质量的影响。对于这两类结合物，发现最大免疫抑制水平关键取决于桥的长度，羧甲基衍生物的效果最佳。还观察到随着酶结构中半抗原取代度的增加，存在免疫再激活的趋势，这在苯巴比妥-羧乙基和羧丙基结合物中尤为明显。据推测，短桥情况下空间位阻对抗体相互作用的影响以及长桥情况下抗体对活性酶位点相互作用的无效性，有助于确定免疫抑制过程的临界桥大小。相反，免疫激活的趋势已初步根据涉及催化位点以外酶区域中半抗原残基的“构象”抗体相互作用的发生来解释。
