Buchanan J W, McIntyre P A, Scheffel U, Wagner H N
J Nucl Med. 1977 Apr;18(4):394-8.
Toadfish serum (TFS) offers several advantages over other proteins as the binder in a competitive-binding assay for vitamin B12. It is unaffected by pH changes in the range 5.6-9.4 or by the addition of human serum albumin. Prolonged incubation with charcoal does not disrupt the TFS-cyanocobalamin bond, and the addition of albumin as a protein source in the standard tubes was proven unnecessary. The binding capacity of TFS does not increase significantly with increasing concentrations of cyanocobalamin as does the binding capacity of intrinsic factor, normal serum, or transcobalamin I. A single extract was prepared from each of 44 sera and measured for vitamin B12 content simultaneously by the TFS assay and the conventional microbiologic method using Lactobacillus leichmannii. The values obtained with TFS were in each instance higher than those obtained by the microbiologic assay (p less than 0.001).
在维生素B12的竞争性结合测定中，蟾鱼血清（TFS）作为结合剂比其他蛋白质具有几个优势。它不受pH值在5.6 - 9.4范围内变化的影响，也不受人血清白蛋白添加的影响。与活性炭长时间孵育不会破坏TFS - 氰钴胺素键，并且已证明在标准管中添加白蛋白作为蛋白质来源是不必要的。TFS的结合能力不会像内因子、正常血清或转钴胺素I的结合能力那样随着氰钴胺素浓度的增加而显著增加。从44份血清中每份制备了一份提取物，并同时通过TFS测定法和使用赖氏乳杆菌的传统微生物学方法测量维生素B12含量。在每种情况下，用TFS获得的值均高于通过微生物学测定获得的值（p小于0.001）。
