| porphin | <protein> A cyclic tetrapyrrole in which the four pyrrole groups are linked by their alpha-carbon atoms via methene (-CH=) bridges, porphin is the partial compund of porphyrins. (14 Oct 1997) |
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| porphine | The unsubstituted cyclic tetrapyrrole nucleus that is the basis of the porphyrins. See: porphyrins. Compare: chlorin, phorbin, corrin. Synonym: porphyrin. (05 Mar 2000) |
| porphobilin | General term denoting intermediates between the monopyrrole, porphobilinogen, and the cyclic tetrapyrrole of haem (a porphin derivative). See: bilin. (05 Mar 2000) |
| porphobilinogen | <chemical> Chemical name: 1H-Pyrrole-3-propanoic acid, 5-(aminomethyl)-4-(carboxymethyl)- (12 Dec 1998) |
| porphobilinogen oxygenase | <enzyme> Porphobilinogen is converted to 5-oxo-porphobilinogen Registry number: EC 1.13.- (26 Jun 1999) |
| porphobilinogen synthase | <enzyme> An enzyme that catalyses the formation of porphobilinogen from two molecules of 5-aminolevulinic acid. Chemical name: 5-Aminolevulinate hydro-lyase (adding 5-aminolevulinate and cyclizing) Registry number: EC 4.2.1.24 (12 Dec 1998) |
| porphobilinogen synthase porphyria | An inherited disorder in which there is a deficiency of porphobilinogen synthase; d-aminolevulinate levels are elevated, leading to neurological disturbances. Synonym: porphobilinogen synthase porphyria. (05 Mar 2000) |
| porphobilinogenase | <enzyme> A combination of uroporphyrinogen I synthase and uroporphyrinogen isomerase which catalyses the formation of uroporphyrinogen III from porphobilinogen; minor descriptor (75-84); on-line and index medicus search ammonia-lyases (75-84) Registry number: EC 5.- (26 Jun 1999) |
| porphyria | A pathological state in man and some lower animals that is often due to genetic factors, is characterised by abnormalities of porphyrin metabolism and results in the excretion of large quantities of porphyrins in the urine and in extreme sensitivity to light. (18 Nov 1997) |
| porphyria cutanea tarda | A form of hepatic porphyria (porphyria, hepatic) characterised by photosensitivity resulting in bullae that rupture easily to form shallow ulcers. This condition occurs in two forms: a sporadic, nonfamilial form that begins in middle age and has normal amounts of uroporphyrinogen decarboxylase with diminished activity in the liver; and a familial form in which there is an autosomal dominant inherited deficiency of uroporphyrinogen decarboxylase in the liver and red blood cells. (12 Dec 1998) |
| porphyria cutanea tarda hereditaria | A form of hepatic porphyria (porphyria, hepatic) characterised by photosensitivity resulting in bullae that rupture easily to form shallow ulcers. This condition occurs in two forms: a sporadic, nonfamilial form that begins in middle age and has normal amounts of uroporphyrinogen decarboxylase with diminished activity in the liver; and a familial form in which there is an autosomal dominant inherited deficiency of uroporphyrinogen decarboxylase in the liver and red blood cells. (12 Dec 1998) |
| porphyria cutanea tarda symptomatica | A form of hepatic porphyria (porphyria, hepatic) characterised by photosensitivity resulting in bullae that rupture easily to form shallow ulcers. This condition occurs in two forms: a sporadic, nonfamilial form that begins in middle age and has normal amounts of uroporphyrinogen decarboxylase with diminished activity in the liver; and a familial form in which there is an autosomal dominant inherited deficiency of uroporphyrinogen decarboxylase in the liver and red blood cells. (12 Dec 1998) |
| porphyria hepatica | A category of porphyria that includes porphyria cutanea tarda, variegate porphyria, and coproporphyria. Synonym: porphyria hepatica. (05 Mar 2000) |
| porphyria, acute intermittent | A form of hepatic porphyria (porphyria, hepatic) characterised by periodic attacks of gastrointestinal disturbances, abdominal colic, paralyses, and psychiatric disorders. The onset of this condition is usually in the third or fourth decade of life. (12 Dec 1998) |
| porphyria, erythrohepatic | A form of porphyria characterised by a wide range of photocutaneous changes, liver disease, and an excess of protoporphyrin. (12 Dec 1998) |