Uroporphyrinogen III Synthetase
An enzyme that catalyzes the cyclization of hydroxymethylbilane to yield UROPORPHYRINOGEN III and water. It is the fourth enzyme in the 8-enzyme biosynthetic pathway of HEME, and is encoded by UROS gene. Mutations of UROS gene result in CONGENITAL ERYTHROPOIETIC PORPHYRIA.
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.
Uroporphyrinogens
Porphyrinogens which are intermediates in heme biosynthesis. They have four acetic acid and four propionic acid side chains attached to the pyrrole rings. Uroporphyrinogen I and III are formed from polypyrryl methane in the presence of uroporphyrinogen III cosynthetase and uroporphyrin I synthetase, respectively. They can yield uroporphyrins by autooxidation or coproporphyrinogens by decarboxylation.
Uroporphyrins
Porphyrinogens
Colorless reduced precursors of porphyrins in which the pyrrole rings are linked by methylene (-CH2-) bridges.
Porphyria, Erythropoietic
An autosomal recessive porphyria that is due to a deficiency of UROPORPHYRINOGEN III SYNTHASE in the BONE MARROW; also known as congenital erythropoietic porphyria. This disease is characterized by SPLENOMEGALY; ANEMIA; photosensitivity; cutaneous lesions; accumulation of hydroxymethylbilane; and increased excretion of UROPORPHYRINS and COPROPORPHYRINS.
Hydroxymethylbilane Synthase
An enzyme that catalyzes the tetrapolymerization of the monopyrrole PORPHOBILINOGEN into the hydroxymethylbilane preuroporphyrinogen (UROPORPHYRINOGENS) in several discrete steps. It is the third enzyme in the 8-enzyme biosynthetic pathway of HEME. In humans, deficiency in this enzyme encoded by HMBS (or PBGD) gene results in a form of neurological porphyria (PORPHYRIA, ACUTE INTERMITTENT). This enzyme was formerly listed as EC 4.3.1.8
Porphyrias
A diverse group of metabolic diseases characterized by errors in the biosynthetic pathway of HEME in the LIVER, the BONE MARROW, or both. They are classified by the deficiency of specific enzymes, the tissue site of enzyme defect, or the clinical features that include neurological (acute) or cutaneous (skin lesions). Porphyrias can be hereditary or acquired as a result of toxicity to the hepatic or erythropoietic marrow tissues.
Porphyrins
A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.
Porphobilinogen
Porphobilinogen is a porphyrin precursor, specifically the organic compound intermediate in the biosynthesis of heme and chlorophyll, formed by the condensation of two pyrrole molecules in the liver and other tissues.
Coproporphyrinogens
Porphyrinogens which are intermediates in the heme biosynthesis. They have four methyl and four propionic acid side chains attached to the pyrrole rings. Coproporphyrinogens I and III are formed in the presence of uroporphyrinogen decarboxylase from the corresponding uroporphyrinogen. They can yield coproporphyrins by autooxidation or protoporphyrin by oxidative decarboxylation.
Methyltransferases
Tetrapyrroles
Porphobilinogen Synthase
An enzyme that catalyzes the formation of porphobilinogen from two molecules of 5-aminolevulinic acid. EC 4.2.1.24.
Porphyria Cutanea Tarda
An autosomal dominant or acquired porphyria due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in the LIVER. It is characterized by photosensitivity and cutaneous lesions with little or no neurologic symptoms. Type I is the acquired form and is strongly associated with liver diseases and hepatic toxicities caused by alcohol or estrogenic steroids. Type II is the familial form.
Carboxy-Lyases
Ammonia-Lyases
Heme
Hydro-Lyases
Pteroylpolyglutamic Acids
Derivatives of folic acid (pteroylglutamic acid). In gamma-glutamyl linkage they are found in many tissues. They are converted to folic acid by the action of pteroylpolyglutamate hydrolase or synthesized from folic acid by the action of folate polyglutamate synthetase. Synthetic pteroylpolyglutamic acids, which are in alpha-glutamyl linkage, are active in bacterial growth assays.
Isomerases
Aminolevulinic Acid
A compound produced from succinyl-CoA and GLYCINE as an intermediate in heme synthesis. It is used as a PHOTOCHEMOTHERAPY for actinic KERATOSIS.
Chlorobenzenes
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Decarboxylation
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
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.