Search results
Results from the WOW.Com Content Network
Porphobilinogen (PBG) is an organic compound that occurs in living organisms as an intermediate in the biosynthesis of porphyrins, which include critical substances like hemoglobin and chlorophyll. [ 1 ]
The most well-known health issue involving porphobilinogen deaminase is acute intermittent porphyria, an autosomal dominant genetic disorder where insufficient hydroxymethylbilane is produced, leading to a build-up of porphobilinogen in the cytoplasm. This is caused by a gene mutation that, in 90% of cases, causes decreased amounts of enzyme.
In AIP, over 100 mutations have been identified on the long arm of chromosome 11 at the HMBS gene, which codes for the cytoplasmic enzyme porphobilinogen deaminase. [16] This deficiency prevents heme synthesis, which can not be completed and the metabolite porphobilinogen accumulates in the cytoplasm.
Aminolevulinic acid dehydratase (porphobilinogen synthase, or ALA dehydratase, or aminolevulinate dehydratase) is an enzyme (EC 4.2.1.24) that in humans is encoded by the ALAD gene. [ 5 ] [ 6 ] Porphobilinogen synthase (or ALA dehydratase , or aminolevulinate dehydratase ) synthesizes porphobilinogen through the asymmetric condensation of two ...
Two molecules of dALA are then combined by porphobilinogen synthase to give porphobilinogen (PBG), which contains a pyrrole ring. Four PBGs are then combined through deamination into hydroxymethyl bilane (HMB), which is hydrolysed to form the circular tetrapyrrole uroporphyrinogen III. This molecule undergoes a number of further modifications.
Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme. [ 4 ] Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme , the chlorins , bacteriochlorins, and chlorophylls .
Porphyria / p ɔːr ˈ f ɪr i ə / is a group of disorders in which substances called porphyrins build up in the body, adversely affecting the skin or nervous system. [1] The types that affect the nervous system are also known as acute porphyria, as symptoms are rapid in onset and short in duration. [1]
HMB is generated from four molecules of porphobilinogen by the enzyme porphobilinogen deaminase: [2] The enzyme uroporphyrinogen III synthase closes the chain to form uroporphyrinogen III : [ 2 ] Uroporphyrinogen III is a porphyrinogen , which is a class of compounds with the hexahydroporphine macrocycle .