Methylmalonyl-CoA Mutase: An enzyme that catalyzes the conversion of methylmalonyl-CoA to succinyl-CoA by transfer of the carbonyl group. It requires a cobamide coenzyme. A block in this enzymatic conversion leads to the metabolic disease, methylmalonic aciduria. EC 22.214.171.124.CobamidesPropionibacterium: A genus of gram-positive, rod-shaped bacteria whose cells occur singly, in pairs or short chains, in V or Y configurations, or in clumps resembling letters of the Chinese alphabet. Its organisms are found in cheese and dairy products as well as on human skin and can occasionally cause soft tissue infections.Methylmalonic Acid: A malonic acid derivative which is a vital intermediate in the metabolism of fat and protein. Abnormalities in methylmalonic acid metabolism lead to methylmalonic aciduria. This metabolic disease is attributed to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA.Isomerases: A class of enzymes that catalyze geometric or structural changes within a molecule to form a single product. The reactions do not involve a net change in the concentrations of compounds other than the substrate and the product.(from Dorland, 28th ed) EC 5.Amino Acid Metabolism, Inborn Errors: Disorders affecting amino acid metabolism. The majority of these disorders are inherited and present in the neonatal period with metabolic disturbances (e.g., ACIDOSIS) and neurologic manifestations. They are present at birth, although they may not become symptomatic until later in life.Acyl Coenzyme A: S-Acyl coenzyme A. Fatty acid coenzyme A derivatives that are involved in the biosynthesis and oxidation of fatty acids as well as in ceramide formation.Methylmalonyl-CoA Decarboxylase: A carboxy-lyase that catalyzes the decarboxylation of (S)-2-Methyl-3-oxopropanoyl-CoA to propanoyl-CoA. In microorganisms the reaction can be coupled to the vectorial transport of SODIUM ions across the cytoplasmic membrane.Hydroxocobalamin: Injectable form of VITAMIN B 12 that has been used therapeutically to treat VITAMIN B 12 DEFICIENCY.Vitamin B 12: A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.Methylobacterium extorquens: A species of METHYLOBACTERIUM which can utilize acetate, ethanol, or methylamine as a sole carbon source. (From Bergey's Manual of Determinative Bacteriology, 9th ed)5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase: An enzyme that catalyzes the formation of methionine by transfer of a methyl group from 5-methyltetrahydrofolate to homocysteine. It requires a cobamide coenzyme. The enzyme can act on mono- or triglutamate derivatives. EC 126.96.36.199.Phosphoglycerate Mutase: An enzyme that catalyzes the conversion of 2-phospho-D-glycerate to 3-phospho-D-glycerate. EC 188.8.131.52.MalonatesPropionates: Derivatives of propionic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxyethane structure.Metabolism, Inborn Errors: Errors in metabolic processes resulting from inborn genetic mutations that are inherited or acquired in utero.Bisphosphoglycerate Mutase: An enzyme that catalyzes the transfer of phosphate from C-3 of 1,3-diphosphoglycerate to C-2 of 3-phosphoglycerate, forming 2,3-diphosphoglycerate. EC 184.108.40.206.Veillonella: A genus of gram-negative, anaerobic cocci parasitic in the mouth and in the intestinal and respiratory tracts of man and other animals.Carboxyl and Carbamoyl Transferases: A group of enzymes that catalyze the transfer of carboxyl- or carbamoyl- groups. EC 2.1.3.Deuterium: Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.Cobalt: A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.Racemases and Epimerases: Enzymes that catalyze inversion of the configuration around an asymmetric carbon in a substrate having one (racemase) or more (epimerase) center(s) of asymmetry. (Dorland, 28th ed) EC 5.1.Malonyl Coenzyme A: A coenzyme A derivative which plays a key role in the fatty acid synthesis in the cytoplasmic and microsomal systems.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.