ALAD - Delta-aminolevulinic acid dehydratase - human protein (Function)
 
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ALAD »  Delta-aminolevulinic acid dehydratase   [ EC 4.2.1.24 ]  (ALADH)
 
Protein also known as:  Porphobilinogen synthase.
Gene name:  ALAD
Family name: ALAD
Entry whose protein(s) existence is based on evidence at protein level
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1 39 2
GENE REF ISO

Function

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Overview 
Catalyzes an early step in the biosynthesis of tetrapyrroles. Binds two molecules of 5-aminolevulinate per subunit, each at a distinct site, and catalyzes their condensation to form porphobilinogen.  
3
  • UniProtKB
GO molecular function 
Catalytic activitydefinition[GO:0003824]  
1
  • PINC
Identical protein bindingdefinition[GO:0042802]  
1
  • UniProtKB
Lead ion bindingdefinition[GO:0032791]  
1
  • UniProtKB
Porphobilinogen synthase activitydefinition[GO:0004655]  
1
  • UniProtKB
Zinc ion bindingdefinition[GO:0008270]  
1
  • UniProtKB
GO biological process 
Cellular response to interleukin-4definition[GO:0071353] silver  
1
  • Ortholog Compara
Cellular response to lead iondefinition[GO:0071284] silver  
1
  • Ortholog Compara
Heme biosynthetic processdefinition[GO:0006783]  
1
  • UniProtKB
Protein homooligomerizationdefinition[GO:0051260]  
1
  • UniProtKB
Protoporphyrinogen IX biosynthetic processdefinition[GO:0006782]  
1
  • UniPathway
Response to activitydefinition[GO:0014823] silver  
1
  • Ortholog Compara
Response to aluminum iondefinition[GO:0010044] silver  
1
  • Ortholog Compara
Response to amino aciddefinition[GO:0043200] silver  
1
  • Ortholog Compara
Response to arsenic-containing substancedefinition[GO:0046685] silver  
1
  • Ortholog Compara
Response to cadmium iondefinition[GO:0046686] silver  
1
  • Ortholog Compara
Response to cobalt iondefinition[GO:0032025] silver  
1
  • Ortholog Compara
Response to drugdefinition[GO:0042493] silver  
1
  • Ortholog Compara
Response to ethanoldefinition[GO:0045471] silver  
1
  • Ortholog Compara
Response to fatty aciddefinition[GO:0070542] silver  
1
  • Ortholog Compara
Response to glucocorticoiddefinition[GO:0051384] silver  
1
  • Ortholog Compara
Response to herbicidedefinition[GO:0009635] silver  
1
  • Ortholog Compara
Response to hypoxiadefinition[GO:0001666] silver  
1
  • Ortholog Compara
Response to ionizing radiationdefinition[GO:0010212] silver  
1
  • Ortholog Compara
Response to iron iondefinition[GO:0010039] silver  
1
  • Ortholog Compara
Response to lipopolysaccharidedefinition[GO:0032496] silver  
1
  • Ortholog Compara
Response to mercury iondefinition[GO:0046689] silver  
1
  • Ortholog Compara
Response to methylmercurydefinition[GO:0051597] silver  
1
  • Ortholog Compara
Response to oxidative stressdefinition[GO:0006979] silver  
1
  • Ortholog Compara
Response to platinum iondefinition[GO:0070541] silver  
1
  • Ortholog Compara
Response to selenium iondefinition[GO:0010269] silver  
1
  • Ortholog Compara
Response to vitamin B1definition[GO:0010266] silver  
1
  • Ortholog Compara
Response to vitamin Edefinition[GO:0033197] silver  
1
  • Ortholog Compara
Response to zinc iondefinition[GO:0010043] silver  
1
  • Ortholog Compara
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reaction
EC 4.2.1.24: 2 5-aminolevulinate porphobilinogen + 2 H(2)O.  
4
  • UniProtKB
It requires the following cofactor
 Zn(2+) : Binds 8 zinc ions per octamer. Requires four zinc ions per octamer for full catalytic activity. Can bind up to 2 zinc ions per subunit.  
2
  • UniProtKB
It is regulated in the following manner
Can alternate between a fully active homooctamer and a low-activity homohexamer. A bound magnesium ion may promote the assembly of the fully active homooctamer. The magnesium-binding site is absent in the low-activity homohexamer. Inhibited by compounds that favor the hexameric state. Inhibited by divalent lead ions. The lead ions partially displace the zinc cofactor.  
4
  • UniProtKB
 
More information is available from:
Pathways 
This protein is involved in the following pathway
1
  • UniProtKB
According to KEGG, this protein belongs to the following pathways:
Metabolic pathways  hsa01100+210  
Porphyrin and chlorophyll metabolism  hsa00860+210  
According to Reactome, this protein belongs to the following pathway:
Heme biosynthesis  R-HSA-189451  
 
More information is available from:
 

Biophysicochemical properties

Kinetic parameters
KM 0.09 mM for 5-aminolevulinate at pH 7
Vmax 43 umol/h/mg enzyme at pH 7
Dependence
pH Optimum pH is 6.8-7.3.

Keywords

Biological process 
Heme biosynthesis  definition   [KW-0350]
Porphyrin biosynthesis  definition   [KW-0627]
Molecular function 
Lyase  definition   [KW-0456]
Technical term 
Allosteric enzyme  definition   [KW-0021]
Reference proteome  definition   [KW-1185]
 

Further external links

GeneWiki: ALAD
GenomeRNAi: 210
PRO: PR:P13716