The photolysis of 5'-deoxyadenosylcobalamin under anaerobic conditions.

Abstract Nuclear magnetic resonance and mass spectrometry have been used to confirm that the nucleoside product formed when 5′-deoxyadenosylcobalamin is photolysed under anaerobic conditions is 8,5′-cyclic adenosine. The synthesis of 5′-deoxyadenosylcobalamin, which is tritiated at C 8 of the adenosyl moiety, provides the confirmation that the photolysis mechanism involves a reaction between the 5′-methylene carbon radical and C 8 of the adenine ring.