View source for Aminolevulinic acid synthase

{{protein
| Name = aminolevulinate, delta-, synthase 1
| caption = 
| image = 
| width = 
| HGNCid = 396
| Symbol = ALAS1
| AltSymbols = ALAS3, ALAS
| EntrezGene = 211
| OMIM = 125290
| RefSeq = NM_000688
| UniProt = P13196
| PDB = 
| ECnumber = 2.3.1.37
| Chromosome = 3
| Arm = p
| Band = 21
| LocusSupplementaryData = 
}}
{{protein
| Name = aminolevulinate, delta-, synthase 2
| caption = 
| image = 
| width = 
| HGNCid = 397
| Symbol = ALAS2
| AltSymbols = ASB
| EntrezGene = 212
| OMIM = 301300
| RefSeq = NM_000032
| UniProt = P22557
| PDB = 
| ECnumber = 2.3.1.37
| Chromosome = X
| Arm = p
| Band = 11.21
| LocusSupplementaryData = 
}}
{{SI}}
{{CMG}}



The rate-limiting enzyme in [[porphyrin]] and [[heme]] biosynthesis is '''ALA synthase''', the enzyme ({{EC number|2.3.1.37}}) that catalyses [[glycine]] and [[succinyl-CoA]] into [[D-Aminolevulinic acid]]. In humans, transcription of ALA synthase is tightly controlled by the presence of [[iron|Fe<sup>2+</sup>]]-binding elements, to prevent accumulation of porphyrin intermediates in the absence of iron. There are two forms of ALA synthase in the body. One form is expressed in red blood cell precursor cells, whereas the other is expressed throughout the body. The red blood cell form is coded by a gene on chromosome x, whereas the other form is coded by a gene on chromsome 3. The disease X-linked sideroblastic anemia is caused by mutations in the ALA synthase gene on chromosome X, whereas no diseases are known to be caused by mutations in the other gene. 

ALA synthase removes the [[carboxyl]] group from glycine and the [[coenzyme A|CoA]] from the succinate, forming δ-aminolevulinic acid (dALA), so called because the [[amino]] group is on the fourth carbon atom in the molecule.

[[Image:Heme synth step1.png|thumb|center|300px|Heme synthesis]]

[[Image:Heme_synthesis.png|center|framed|Heme synthesis&mdash;note that some reactions occur in the [[cytoplasm]] and some in the [[mitochondrion]] (yellow)]]

==External links==
* [http://ghr.nlm.nih.gov/gene=alas1 NIH]
* {{cite journal | author = Abu-Farha M, Niles J, Willmore W | title = Erythroid-specific 5-aminolevulinate synthase protein is stabilized by low oxygen and proteasomal inhibition. | journal = Biochem Cell Biol | volume = 83 | issue = 5 | pages = 620-30 | year = 2005 | id = PMID 16234850}}

{{Acyltransferases}}
{{Porphyrin biosynthesis enzymes}}


[[Category:EC 2.3.1]]
[[Category:Hematology]]

[[de:Δ-Aminolävulinatsynthase]]

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