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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The typical biochemical findings include elevated levels of uroporphyrin in urine with levels even upto sixty times the normal.
The activation of uroporphyrin deposited in the skin by ultraviolet light induces the production of oxidized reactive substances that excessively activate collagenase.
It also implies increased plasma or urine porphyrins formed before the UROD step such as uroporphyrin, heptacarboxylporphyrin, hexacarboxylporphyrin, and pentacarboxylporphyrin (urine analysis not validated for patients with end-stage renal disease (ESRD)) with concomitant normal levels of coproporphyrins [7].
It results in an increase in uroporphyrin I and coproporphyrin I in plasma, red blood cells, urine, feces, and in different tissues.
Differential potency of atropisomers of polychlorinated biphenyls on cytochrome P450 induction and uroporphyrin accumulation in the chick embryo hepatocyte culture.
The combination of elevated urinary and erythrocyte uroporphyrin I levels is specific for EP.
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).
Results similar to those for HPD were obtained by others [20] (in the same buffer, but at 25[degrees]C) with PII (5.4 x [10.sup.-5]) and typical porphyrins (HP, 4.7 x [10.sup.-5]; uroporphyrin, 2.8 x [10.sup.-5]).
Urine porphyrins were shown on thin-layer chromatography (TLC) to be mostly uroporphyrin with a trace of heptacarboxylic porphyrin.
Congenital erythropoietic porphyria (CEP) is one of the rare forms of an intriguing group of metabolic disorders known as porphyria, caused by an autosomal recessive inherited deficiency of the uroporphyrin III cosynthase enzyme.
CYP3A-inducing agents and the attenuation of uroporphyrin accumulation and excretion in a rat model of porphyria cutanea tarda.