Uroporphyrin


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uroporphyrin

[¦yu̇r·ə′pȯr·fə·rən]
(biochemistry)
Any of several isomeric, metal-free porphyrins, occurring in small quantities in normal urine and feces; molecule has four acetic acid (‒CH2COOH) and four propionic acid (‒CH2CH2COOH) groups.

Uroporphyrin

 

any of the pigments of the porphyrin group that are similar in structure and that occur primarily in urine and feces. In a number of pathological states (porphyria, certain types of poisoning), the content of one uroporphyrin in human urine sharply increases (to several hundred mg). Uroporphyrins have been found in the shells of pearl oysters and in planarians.

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His urinary porphyrin excretion profile showed greatly elevated porphyrin concentrations (10- to 13-fold) with a preponderance of uroporphyrin, typical of acute porphyria.
Porphobilinogen was found to be strongly positive in the analysis of a spot urine sample, and her uroporphyrin, corpoporphyrin and total porphyrin levels were found to be elevated in a 24-hour urine collection.
6) Abnormal porphyrin metabolism, a characteristic of diseases usually inherited as an enzyme deficiency and resulting in abnormal synthesis of photodynamic agents, including uroporphyrin and coproporphyrin, can result in photosensitization.
Differential potency of atropisomers of polychlorinated biphenyls on cytochrome P450 induction and uroporphyrin accumulation in the chick embryo hepatocyte culture.
The steps in the heme synthesis pathway that are most vulnerable to heavy metal inhibition are those that involve the enzymes uroporphyrin decarboxylase (UROD) and coproporphyrinogen oxidase (CPOX).
Quantum yields and kinetics of the photobleaching of hematoporphyrin, photofrin II, tetra(4-sulfonatophenyl)-porphine and uroporphyrin.
CYP3A-inducing agents and the attenuation of uroporphyrin accumulation and excretion in a rat model of porphyria cutanea tarda.
PbAs had additive effects on urinary excretion of coproporphyrin, but less than additive for uroporphyrin.
Analysis has suggested that this fluorescence results from a mixture of porphyrins, including a mixture of uroporphyrin, harderoporphyrin, isoharderoporphyrin, protoporphyrin, and pentacarboxylic porphyrin loosely bound to proteins, coupled with a second group that may be derivatives of a dicarboxylic porphyrin tightly bound to albumin (14, 17).
For example, in erythropoietic protoporphyria (EPP) there is an excess of protoporphyrin (PP) while in congenital erythropoietic porphyria (Gunther's disease) there are high levels of uroporphyrin (UP), the photosensitivity being more severe in this case (26).
In 66 cases (35 symptomatic and 31 symptom free), the diagnosis was based on low erythrocyte PBGD activity (<55 [micro]mol uroporphyrin x [h.
Key words: coproporphyrin I, coproporphyrin III, hexachlorobenzene, neonates, porphyria, uroporphyrin.