An enzyme that catalyzes the formation of porphobilinogen from two molecules of 5-aminolevulinic acid. EC 220.127.116.11.
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 18.104.22.168
A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.
Porphyria, Acute Intermittent
An autosomal dominant porphyria that is due to a deficiency of HYDROXYMETHYLBILANE SYNTHASE in the LIVER, the third enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features are recurrent and life-threatening neurologic disturbances, ABDOMINAL PAIN, and elevated level of AMINOLEVULINIC ACID and PORPHOBILINOGEN in the urine.
Protein Structure, Quaternary
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.
A compound produced from succinyl-CoA and GLYCINE as an intermediate in heme synthesis. It is used as a PHOTOCHEMOTHERAPY for actinic KERATOSIS.
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.
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.
A group of metabolic diseases due to deficiency of one of a number of LIVER enzymes in the biosynthetic pathway of HEME. They are characterized by the accumulation and increased excretion of PORPHYRINS or its precursors. Clinical features include neurological symptoms (PORPHYRIA, ACUTE INTERMITTENT), cutaneous lesions due to photosensitivity (PORPHYRIA CUTANEA TARDA), or both (HEREDITARY COPROPORPHYRIA). Hepatic porphyrias can be hereditary or acquired as a result of toxicity to the hepatic tissues.
Fluids and Secretions
Chromatography, High Pressure Liquid
An alkaloid found in the seeds of STRYCHNOS NUX-VOMICA. It is a competitive antagonist at glycine receptors and thus a convulsant. It has been used as an analeptic, in the treatment of nonketotic hyperglycinemia and sleep apnea, and as a rat poison.
Encyclopedias as Topic
A disease caused by a deficiency of thiamine (vitamin B1) and characterized by polyneuritis, cardiac pathology, and edema. The epidemic form is found primarily in areas in which white (polished) rice is the staple food, as in Japan, China, the Philippines, India, and other countries of southeast Asia. (Dorland, 27th ed)
A megaloblastic anemia occurring in children but more commonly in later life, characterized by histamine-fast achlorhydria, in which the laboratory and clinical manifestations are based on malabsorption of vitamin B 12 due to a failure of the gastric mucosa to secrete adequate and potent intrinsic factor. (Dorland, 27th ed)
Mannosidase Deficiency Diseases
Diseases caused by the loss of one or more enzymes involved in the hydrolysis of mannoside linkages (MANNOSIDASES). The defects in enzyme activity are primarily associated with genetic mutation of the genes that codes for a particular mannosidase isoenzyme.
Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.
Disorders caused by interruption of BONE MINERALIZATION manifesting as OSTEOMALACIA in adults and characteristic deformities in infancy and childhood due to disturbances in normal BONE FORMATION. The mineralization process may be interrupted by disruption of VITAMIN D; PHOSPHORUS; or CALCIUM homeostasis, resulting from dietary deficiencies, or acquired, or inherited metabolic, or hormonal disturbances.
Terminology as Topic
Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.
Holy Roman Empire
A historical and cultural entity dispersed across a wide geographical area under the political domination and influence of ancient Rome, bringing to the conquered people the Roman civilization and culture from 753 B.C. to the beginning of the imperial rule under Augustus in 27 B.C. The early city built on seven hills grew to conquer Sicily, Sardinia, Carthage, Gaul, Spain, Britain, Greece, Asia Minor, etc., and extended ultimately from Mesopotamia to the Atlantic. Roman medicine was almost entirely in Greek hands, but Rome, with its superior water system, remains a model of sanitation and hygiene. (From A. Castiglioni, A History of Medicine, 2d ed pp196-99; from F. H. Garrison, An Introduction to the History of Medicine, 4th ed, pp107-120)