ALAD |
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PFAM accession number: | PF00490 |
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Interpro abstract (IPR001731): | Tetrapyrroles are large macrocyclic compounds derived from a common biosynthetic pathway [ (PUBMED:16564539) ]. The end-product, uroporphyrinogen III, is used to synthesise a number of important molecules, including vitamin B12, haem, sirohaem, chlorophyll, coenzyme F430 and phytochromobilin [ (PUBMED:17227226) ].
This entry represents delta-aminolevulinic acid dehydratase (ALAD), also known as porphobilinogen (PBG) synthase (PBGS, or 5-aminoaevulinic acid dehydratase EC 4.2.1.24 ), which functions during the second stage of tetrapyrrole biosynthesis. This enzyme catalyses a Knorr-type condensation reaction between two molecules of ALA to generate porphobilinogen, the pyrrolic building block used in later steps [ (PUBMED:17311232) ]. The structure of the enzyme is based on a TIM barrel topology made up of eight identical subunits, where each subunit binds to a metal ion that is essential for activity, usually zinc (in yeast, mammals and certain bacteria) or magnesium (in plants and other bacteria). A lysine has been implicated in the catalytic mechanism [ (PUBMED:3092810) ]. The lack of PBGS enzyme causes a rare porphyric disorder known as ALAD porphyria, which appears to involve conformational changes in the enzyme [ (PUBMED:17236137) ]. |
GO process: | tetrapyrrole biosynthetic process (GO:0033014) |
GO function: | porphobilinogen synthase activity (GO:0004655), metal ion binding (GO:0046872) |
This is a PFAM domain. For full annotation and more information, please see the PFAM entry ALAD