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 126.96.36.199.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.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.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.Propionates: Derivatives of propionic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxyethane structure.Ornithine Decarboxylase: A pyridoxal-phosphate protein, believed to be the rate-limiting compound in the biosynthesis of polyamines. It catalyzes the decarboxylation of ornithine to form putrescine, which is then linked to a propylamine moiety of decarboxylated S-adenosylmethionine to form spermidine.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.MalonatesAmino 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.Propionibacterium: 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.Carboxy-Lyases: Enzymes that catalyze the addition of a carboxyl group to a compound (carboxylases) or the removal of a carboxyl group from a compound (decarboxylases). EC 4.1.1.Glutamate Decarboxylase: A pyridoxal-phosphate protein that catalyzes the alpha-decarboxylation of L-glutamic acid to form gamma-aminobutyric acid and carbon dioxide. The enzyme is found in bacteria and in invertebrate and vertebrate nervous systems. It is the rate-limiting enzyme in determining GAMMA-AMINOBUTYRIC ACID levels in normal nervous tissues. The brain enzyme also acts on L-cysteate, L-cysteine sulfinate, and L-aspartate. EC 188.8.131.52.Dopa Decarboxylase: One of the AROMATIC-L-AMINO-ACID DECARBOXYLASES, this enzyme is responsible for the conversion of DOPA to DOPAMINE. It is of clinical importance in the treatment of Parkinson's disease.Histidine Decarboxylase: An enzyme that catalyzes the decarboxylation of histidine to histamine and carbon dioxide. It requires pyridoxal phosphate in animal tissues, but not in microorganisms. EC 184.108.40.206.Adenosylmethionine Decarboxylase: An enzyme that catalyzes the decarboxylation of S-adenosyl-L-methionine to yield 5'-deoxy-(5'-),3-aminopropyl-(1), methylsulfonium salt. It is one of the enzymes responsible for the synthesis of spermidine from putrescine. EC 220.127.116.11.Uroporphyrinogen Decarboxylase: An enzyme that catalyzes the decarboxylation of UROPORPHYRINOGEN III to coproporphyrinogen III by the conversion of four acetate groups to four methyl groups. It is the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME. Several forms of cutaneous PORPHYRIAS are results of this enzyme deficiency as in PORPHYRIA CUTANEA TARDA; and HEPATOERYTHROPOIETIC PORPHYRIA.Orotidine-5'-Phosphate Decarboxylase: Orotidine-5'-phosphate carboxy-lyase. Catalyzes the decarboxylation of orotidylic acid to yield uridylic acid in the final step of the pyrimidine nucleotide biosynthesis pathway. EC 18.104.22.168.Tyrosine Decarboxylase: A pyridoxal-phosphate protein that catalyzes the conversion of L-tyrosine to tyramine and carbon dioxide. The bacterial enzyme also acts on 3-hydroxytyrosine and, more slowly, on 3-hydroxyphenylalanine. (From Enzyme Nomenclature, 1992) EC 22.214.171.124.PolyaminesEflornithine: An inhibitor of ORNITHINE DECARBOXYLASE, the rate limiting enzyme of the polyamine biosynthetic pathway.Putrescine: A toxic diamine formed by putrefaction from the decarboxylation of arginine and ornithine.