Mori N, Nakamura T, Koyama J
J Biochem. 1977 Jul;82(1):1-8. doi: 10.1093/oxfordjournals.jbchem.a131657.
Administration of an excessive dose of Bacillus subtilis alpha-amylase [EC 3.2.1.1, alpha-1,4-glucan 4-glucanohydrolase] (BalphaA) induced the production of non-precipitating (non-ppt) IgG2 antibody in guinea pigs, whereas immunization with a normal dose produced precipitating (ppt) IgG1 and IgG2 antibodies. The non-ppt IgG2 antibody thus produced could be isolated from the coexisting ppt IgG2 antibody by means of the precipitin reaction at maximum precipitation. The non-ppt antibody was incapable of forming a precipitin arc with BalphaA in a conventional agar plate. In the presence of 4% polyethylene glycol (PEG), however, it formed a single arc which fused completely with those of the ppt IgG1 and IgG2 antibodies. The non-ppt antibody could not fix complement, but inhibited BalphaA activity, though with less efficiency than the ppt antibodies. These properties of the non-ppt IgG2 antibody may be due to a low affinity for BalphaA, since both gel filtration and precipitation of soluble antigen-antibody complexes with 20% PEG showed that the antibody was easily dissociable from BalphaA.
给豚鼠过量注射枯草芽孢杆菌α-淀粉酶EC 3.2.1.1，α-1,4-葡聚糖4-葡聚糖水解酶可诱导产生非沉淀性(non-ppt)IgG2抗体，而用正常剂量免疫则产生沉淀性(ppt)IgG1和IgG2抗体。如此产生的非沉淀性IgG2抗体可在最大沉淀时通过沉淀反应从共存的沉淀性IgG2抗体中分离出来。在传统琼脂平板中，非沉淀性抗体无法与BalphaA形成沉淀弧。然而，在4%聚乙二醇(PEG)存在的情况下，它形成了一条单一的弧，该弧与沉淀性IgG1和IgG2抗体的弧完全融合。非沉淀性抗体不能固定补体，但能抑制BalphaA的活性，不过效率低于沉淀性抗体。非沉淀性IgG2抗体的这些特性可能是由于其对BalphaA的亲和力较低，因为凝胶过滤和用20%PEG沉淀可溶性抗原-抗体复合物均表明该抗体很容易与BalphaA解离。
