Adenosylcobalamin is an active form of Vitamin B12. This form of B12 is our mitochondrial B12 and as such it is essential for us to produce energy at the cellular level. Adenosylcobalamin assists in the conversion of methylmalonyl-CoA to succinyl-CoA a direct intermediate in the citric acid cycle/Krebs cycle (our energy cycle that creates ATP and CoQ10.). High levels of methylmalonic acid (MMA) in the blood or urine point to an adenosylcobalamin deficiency. Deficiency of adenosylcobalamin may lead to fatty acid and myelin issues.