Ithakissios D S, Kubiatowicz D O, Windorski D C, Wicks J H
Clin Chem. 1977 Nov;23(11):2043-7.
We compare serum proteins from rainbow trout, chinook salmon, coho salmon, and oyster toadfish with intrinsic factor as binding proteins in a simplified radioassay for B12. Regression analysis of B12 values, determined in 21 serum samples, shows good correlation (r greater than .975) between results for the fish sera and intrinsic factor. The accuracy of the five assays, as evaluated by analytical recovery of B12 added to pooled human serum, ranges from 90 to 110%. Intra-assay precision ranges from 2.6% for coho salmon serum to 5.5% for intrinsic factor, Ionic strength and variations in pH influence binding of [57Co]vit B12 to the fish sera. Maximum binding occurs from pH 6 to 10 at an ionic strength of 0.1 for all sera. The sera are stable for longer than two years when stored at -20 degrees C. Important advantages of fish sera are their high binding capacity (typical assay dilutions range from 1500-fold for trout serum to more than 50 000-fold for chinook salmon); high affinity for B12 (K greater than 10(12) liter/mol); their relative constant binding characteristics as compared to commercial intrinsic factor preparations; and the finding that the accuracy of radioassays with use of fish sera is not significantly affected by the amount of B12 or human serum proteins present.
我们将虹鳟鱼、银大麻哈鱼、红大麻哈鱼和牡蛎蟾鱼的血清蛋白与内因子作为结合蛋白，用于简化的维生素B12放射分析中。对21份血清样本中维生素B12值进行回归分析，结果显示鱼血清与内因子的检测结果之间具有良好的相关性（r大于0.975）。通过添加到混合人血清中的维生素B12的分析回收率评估，这五种检测方法的准确度在90%至110%之间。批内精密度范围从红大麻哈鱼血清的2.6%到内因子的5.5%。离子强度和pH值的变化会影响[57Co]维生素B12与鱼血清的结合。所有血清在离子强度为0.1时，pH值从6到10时结合力最大。血清在-20℃储存时稳定超过两年。鱼血清的重要优点包括其高结合能力（典型检测稀释倍数范围从鳟鱼血清的1500倍到银大麻哈鱼的超过50000倍）；对维生素B12的高亲和力（K大于10(12)升/摩尔）；与商业内因子制剂相比，其相对恒定的结合特性；以及使用鱼血清的放射分析准确度不受维生素B12或人血清蛋白含量显著影响的发现。
