Preparation of Radioactive Labelled (57Co) Sulfitocobalamin |
| |
Authors: | James A Begley Carol Horch Charles A Hall |
| |
Institution: | Veterans Administration Hospital and the Department of Medicine , Albany Medical College , Albany, New York, 12208 |
| |
Abstract: | Abstract Farquharson and Adams (Br. J. Nutr. 36, 127-135 (1976)) have identified sulfitocobalamin (S03?Cbl) as one of the naturally occurring cobalamins (Cbls) in foods. We have devised a method of making radioactive labelled S03?Cbl for invivo and in vitro studies of this form of Cbl. 57Co labelled cyanocobalamin (57Co CN-Cbl) was acid photolyzed to 57Co hydroxocobalamin (57Co OH-Cbl) followed by ligand substitution with S03 ?2 ion from aqueous sodium (meta) bisulfite in the dark. The resulting 57Co SO3?Cbl was purified by organic extraction and cation ex-change chromatography. The final preparation was >99% Co57 S03?Cbl with an overall yield of >70%, stable for up to four weeks at 20°C in the dark, and capable of binding to the human Cbl 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 S03?Cbl for biological studies. |
| |
Keywords: | |
|
|