The primary cause of this disorder is a deficiency of uroporphyrinogen decarboxylase ( UROD ), a cytosolic enzyme that is a step in the enzymatic pathway that leads to the synthesis of heme.
12.
The combination of this increased demand and reduced activity of uroporphyrinogen decarboxylase disrupts heme production and allows byproducts of the process to accumulate in the body, triggering the signs and symptoms of porphyria cutanea tarda.
13.
Uroporphyrinogen ( urogen ) III methyltransferase ( UMT ) catalyzes a reaction that yields two fluorescent products which produce a red-orange fluorescence in the 590-770 nm range when illuminated with ultraviolet light.
14.
Four molecules of porphobilinogen combine to form a linear tetrapyrrole, which cyclizes to uroporphyrinogen III . Oxidation and side-chain modifications lead to the synthesis of protoporphyrin IX, which acquires an iron atom to form heme.
15.
Uroporphyrinogen III decarboxylase ( UroD ) is a homodimeric enzyme (, ) that catalyzes the fifth step in heme biosynthesis : the elimination of carboxyl groups from the four acetate side chains of uroporphyrinogen III to yield coproporphyrinogen III.
16.
Uroporphyrinogen III decarboxylase ( UroD ) is a homodimeric enzyme (, ) that catalyzes the fifth step in heme biosynthesis : the elimination of carboxyl groups from the four acetate side chains of uroporphyrinogen III to yield coproporphyrinogen III.
17.
It is thought to do so by causing oxidative damage to liver cells, resulting in oxidized species of uroporphyrinogen that inhibit the activity of hepatic UROD . It is also felt to increase the uptake of iron in liver cells, leading to further oxidation of uroporphyrinogen by the release of activated oxygen species.
18.
It is thought to do so by causing oxidative damage to liver cells, resulting in oxidized species of uroporphyrinogen that inhibit the activity of hepatic UROD . It is also felt to increase the uptake of iron in liver cells, leading to further oxidation of uroporphyrinogen by the release of activated oxygen species.
19.
The difference between the two forms, is the arrangements of the four propionic acid ( " P " groups ) and the four acetic acid groups ( " A " groups ), where non-enzyamtically conversion into uroporphyrinogen I results in an AP-AP-AP-AP symmetry, whereas the enzymatically conversion into uroporphyrinogen III lead to a reversed AP-group and hence an AP-AP-AP-PA arrangement.
20.
The difference between the two forms, is the arrangements of the four propionic acid ( " P " groups ) and the four acetic acid groups ( " A " groups ), where non-enzyamtically conversion into uroporphyrinogen I results in an AP-AP-AP-AP symmetry, whereas the enzymatically conversion into uroporphyrinogen III lead to a reversed AP-group and hence an AP-AP-AP-PA arrangement.
