protoporphyrin

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protoporphyrin

 [pro″to-por´fĭ-rin]
a porphyrin whose iron complex united with protein occurs in hemoglobin, myoglobin, and certain respiratory pigments. It is accumulated and excreted excessively in the feces in erythropoietic protoporphyria and variegate porphyria.

protoporphyrin

/pro·to·por·phy·rin/ (-por´fĭ-rin) any of several porphyrin isomers, one of which is an intermediate in heme biosynthesis; it is accumulated and excreted excessively in feces in erythropoietic protoporphyria and variegate porphyria.

protoporphyrin

(prō′tō-pôr′fə-rĭn)
n.
A metal-free porphyrin, C34H34N4O4, that combines with ferrous iron to form the heme group in hemoglobin and myoglobin, and with ferric iron to form the hemin group in catalase and some cytochromes.

protoporphyrin

[prō′tōpôr′firin]
Etymology: Gk, protos + porphyros
a kind of porphyrin that combines with iron and protein to form various important organic molecules, including catalase, hemoglobin, and myoglobin. See also heme.

protoporphyrin

A porphyrin occurring in the course of the synthesis of HAEMOGLOBIN. Excess of this porphyrin, protoporphyria, causes intense itching, swelling and redness of the skin on exposure to sunlight and leads to a strikingly weatherbeaten appearance.

Protoporphyrin

A precursor molecule to the porphyrin molecule.
Mentioned in: Porphyrias

protoporphyrin

a porphyrin whose iron complex united with protein occurs in hemoglobin, myoglobin and certain respiratory pigments.

protoporphyrin III
combines with 4 moles of iron to form the heme moiety of hemoglobin.
References in periodicals archive ?
Excretion of fecal protoporphyrin is increased in 20% of AIP patients even in remission; thus it cannot be used to distinguish variegate porphyria from AIP.
Increased erythrocyte uroporphyrinogen-I-synthetase, S-aminolevulinic acid dehydratase and protoporphyrin in hemolytic anemias.
1]) Mutation n (b) [down N arrow] (c) Positive 85 71 14 Negative 43 10 33 Total 128 Urine (a) PGB (<9 [micro]mol/L) Mutation n [up N arrow] Positive 81 69 12 Negative 41 12 29 Total 122 Urine (a) ALA (<34 [micro]mol/L) Mutation n [up N arrow] Positive 78 48 30 Negative 41 4 37 Total 119 Urine (a) Uroporphyrin (<36 nmol) Mutation n [up N arrow] Positive 67 48 19 Negative 30 1 29 Total 97 Urine (a) Coproporphyrin (<230 nmol/day) Mutation n [up N arrow] Positive 70 47 23 Negative 31 4 27 Total 101 Feces (a) Coproporphyrin (<100 nmol/g) Mutation n [up N arrow] Positive 55 2 53 Negative 26 0 26 Total 81 Feces (a) Protoporphyrin (<130 nmol/g) Mutation n [up N arrow] Positive 55 11 44 Negative 25 1 24 Total 80 (a) Values in parentheses are the reference intervals.
All laboratories submitting results for erythrocyte protoporphyrin fractions found predominantly free protoporphyrin in the erythropoietic protoporphyria (EPP) patient.
The percentage of laboratories achieving desirable analytical quality on average for all distributions was, for ALA, 76%; for PBG, 57%; for fecal porphyrins, 63%; for erythrocyte protoporphyrin, 53%; and for plasma porphyrins, 43%.
About a fourth of the participants would have analyzed erythrocyte protoporphyrin in the acute patients, which is of little value unless ALA-dehydratase deficiency or lead intoxication is suspected (18).
Fischer and his colleagues succeeded in the complete syntheses of protoporphyrin and heme in 1929, for which he subsequently received the Nobel Prize.
Metal-free protoporphyrin in erythrocytes has been associated with lead poisoning and iron deficiency since the early clinical studies of porphyrins.
Ferrochelatase then catalyzes the chelation of a ferrous ion by protoporphyrin as the terminal reaction in heme formation (Fig.
However, subsequent research on ferrochelatase revealed that this enzyme catalyzes zinc as well as iron chelation by protoporphyrin (12,13).
In contrast to cobalt and iron protoporphyrin, ZnPP was found to affect neither heme biosynthetic enzymes nor cellular actions that depend on hemoproteins.
If the effect of lead in marrow during the state of chronic lead toxicity were through inhibition of ferrochelatase, this enzyme inhibition would be expected to increase metal-free protoporphyrin as found in protoporphyria, an inherited deficiency of ferrochelatase (11).