Aquacobalamin (Vitamin B₁₂_a) Does Not Bind NO in Aqueous Solution. Nitrite Impurities Account for Observed Reaction

Abstract

Numerous reports in recent literature claim that NO binds to aquacobalamine (vitamin B12a) to produce a nitrosyl complex, and that this reaction plays an important role in various biological processes. A careful study of the system has now revealed that there is no reaction between aquacobalamin and NO. The observed reaction is due to the presence of nitrite impurities in aqueous solutions of NO, which react with aquacobalamin to produce the nitrite complex.