Begley J A, Horch C, Hall C A
Prep Biochem. 1978;8(6):411-9. doi: 10.1080/00327487808061659.
Farquharson and Adams (Br. J. Nutr. 36, 127-135 (1976)) have identified sulfitocobalamin (SO3-Cb1) as one of the naturally occurring cobalamins (Cb1s) in foods. We have devised a method of making radioactive labelled SO3-Cb1 for in vivo and in vitro studies of this form of Cb1. 57Co labelled cyanocobalamin (57Co CN-Cb1) was acid photolyzed to 57Co hydroxocobalamin (57Co OH-Cb1) followed by ligand substitution with SO3-2 ion from aqueous sodium (meta) bisulfite in the dark. The resulting 57Co SO3-Cb1 was purified by organic extraction and cation exchange chromatography. The final preparation was greater than 99% 57Co SO3-Cb1 with an overall yield of greater than 70%, stable for up to four weeks at 20 degrees C in the dark, and capable of binding to the human Cb1 binding proteins Transcobalamin II (TC II), Intrinsic factor (IF) and Salivary R. This method allows a simple 1 day preparation of high specific activity labelled 57CO SO3-Cb1 for biological studies.
法夸尔森和亚当斯（《英国营养学杂志》36卷，127 - 135页（1976年））已将亚硫酸钴胺素（SO3 - Cb1）确定为食物中天然存在的钴胺素（Cb1s）之一。我们设计了一种制备放射性标记的SO3 - Cb1的方法，用于对这种形式的Cb1进行体内和体外研究。将57Co标记的氰钴胺素（57Co CN - Cb1）进行酸性光解得到57Co羟钴胺素（57Co OH - Cb1），随后在黑暗中用亚硫酸氢钠水溶液中的SO3 - 2离子进行配体取代。所得的57Co SO3 - Cb1通过有机萃取和阳离子交换色谱法进行纯化。最终制剂中57Co SO3 - Cb1含量大于99%，总产率大于70%，在20℃黑暗条件下可稳定保存长达四周，并且能够与人的Cb1结合蛋白转钴胺素II（TC II）、内因子（IF）和唾液R结合。该方法可在一天内简单地制备出用于生物学研究的高比活度标记的57Co SO3 - Cb1。
