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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.
Heme is produced in all cells, but 80% of all heme is produced in erythropoietic cells in bone marrow and 15% in parenchymal cells in the liver, where turnover of hemoproteins is high. 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 ...
In non-photosynthetic eukaryotes such as animals, insects, fungi, and protozoa, as well as the α-proteobacteria group of bacteria, the committed step for porphyrin biosynthesis is the formation of δ-aminolevulinic acid (δ-ALA, 5-ALA or dALA) by the reaction of the amino acid glycine with succinyl-CoA from the citric acid cycle.
It catalyzes the following reaction, the second step of the biosynthesis of porphyrin: 2 5-Aminolevulinic acid porphobilinogen + 2 H 2 O. It therefore catalyzes the condensation of 2 molecules of 5-aminolevulinate to form porphobilinogen (a precursor of heme, cytochromes and other hemoproteins). This reaction is the first common step in the ...
A salvage pathway is a pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. The term often refers to nucleotide salvage in particular, in which nucleotides (purine and pyrimidine) are synthesized from intermediates in their degradative pathway.
Other DNA and RNA nucleotide bases that are linked to the ribose sugar via a glycosidic bond are thymine, cytosine and uracil (which is only found in RNA). Uridine monophosphate biosynthesis involves an enzyme that is located in the mitochondrial inner membrane and multifunctional enzymes that are located in the cytosol .
All living cells contain both DNA and RNA (except some cells such as mature red blood cells), while viruses contain either DNA or RNA, but usually not both. [15] The basic component of biological nucleic acids is the nucleotide , each of which contains a pentose sugar ( ribose or deoxyribose ), a phosphate group, and a nucleobase . [ 16 ]