 Upon entry to the mitochondria, the 32 amino acid mitochondrial leader sequence at the N-terminus of the protein is cleaved, forming the fully processed monomer.The monomers then associate into homodimers, and bind AdoCbl (one for each monomer active site) to form the final, active holoenzyme form.The "MUT" gene lies on the chromosome location of 6p12.3 and consists of 13 exons, spanning over 35kb.