Vitamin B12 deficiency leads to accumulation of

(D) Methylmalonyl-CoA # Vit B12 deficiency leads to megaloblastic anemia.> B12 (cobalamin) is involved in the isomerization of methylmalonyl coenzyme Ato succinyl coenzyme A, requiring adenosylcobalamin as a prosthetic group on the enzyme methylmalonyl- coenzyme A mutase.> A deficiency of vitamin B12 thus leads to increased levels of methylmalonate, excreted in the urine as methylmalonic acid. Interruption of the succinyl pathway with the build-up of increased levels of methylmalonate and propionate (a precursor) could lead to the formation of abnormal fatty acids that may be incorporated into neuronal lipids.> Beta oxidation of saturated fatty acids with odd number of carbon atoms proceeds as follows: Propionyl CoA with biotin (Propionyl CoA carboxylase) forms methylmalonyl CoA which is converted to succinyl CoA due to methylmalonyl CoA mutase (vitamin B12 as coenzyme) Deficiency of vitamin B12 leads to methylmalonyl aciduria.