Graphical Abstract: No grounded mechanisms for Co-C vitamin B12 coenzyme bond breaking process and subsequent reactions have been found up to now. The influence of the mixing orbitals e.g. Pseudo-Jahn-Teller and similar effects on the reactions paths of bond-cleavage mechanisms of vitamin B12 co-factors must be taken into account. Afterward, the updated mechanisms of vitamin B12 bio-processes can be determined.