ExplorEnz: EC 4.2.1.24

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4.2.1.24

Accepted name:

porphobilinogen synthase

Reaction:

2 5-aminolevulinate = porphobilinogen + 2 H₂O

For diagram of porphyrin biosynthesis (early stages), click here

Glossary:

5-aminolevulinate = δ-aminolevulinate

Other name(s):

aminolevulinate dehydratase; δ-aminolevulinate dehydratase; δ-aminolevulinic acid dehydrase; δ-aminolevulinic acid dehydratase; aminolevulinic dehydratase; δ-aminolevulinic dehydratase; 5-levulinic acid dehydratase; 5-aminolevulinate hydro-lyase (adding 5-aminolevulinate and cyclizing); hemB (gene name)

Systematic name:

5-aminolevulinate hydro-lyase (adding 5-aminolevulinate and cyclizing; porphobilinogen-forming)

Comments:

The enzyme catalyses the asymmetric condensation and cyclization of two 5-aminolevulinate molecules, which is the first common step in the biosynthesis of tetrapyrrole pigments such as porphyrin, chlorophyll, vitamin B₁₂, siroheme, phycobilin, and cofactor F₄₃₀. The enzyme is widespread, being essential in organisms that carry out respiration, photosynthesis, or methanogenesis. The enzymes from most organisms utilize metal ions (Zn²⁺, Mg²⁺, K⁺, and Na⁺) as cofactors that reside at multiple sites, including the active site and allosteric sites. Enzymes from archaea, yeast, and metazoa (including human) contain Zn²⁺ at the active site. In humans, the enzyme is a primary target for the environmental toxin Pb. The enzymes from some organisms utilize a dynamic equilibrium between architecturally distinct multimeric assemblies as a means for allosteric regulation.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9036-37-7

References:

1.	Gibson, K.D., Neuberger, A. and Scott, J.J. The purification and properties of δ-aminolaevulic acid dehydrase. Biochem. J. 61 (1955) 618–629. [PMID: 13276347]
2.	Komai, H. and Neilands, J.B. The metalloprotein nature of Ustilago δ-aminolevulinate dehydratase. Biochim. Biophys. Acta 171 (1969) 311–320. [DOI] [PMID: 5773436]
3.	Yamasaki, H. and Moriyama, T. δ-Aminolevulinic acid dehydratase of Mycobacterium phlei. Biochim. Biophys. Acta 227 (1971) 698–705. [DOI] [PMID: 4998716]
4.	Mitchell, L.W. and Jaffe, E.K. Porphobilinogen synthase from Escherichia coli is a Zn(II) metalloenzyme stimulated by Mg(II). Arch. Biochem. Biophys. 300 (1993) 169–177. [DOI] [PMID: 8424649]
5.	Jaffe, E.K., Ali, S., Mitchell, L.W., Taylor, K.M., Volin, M. and Markham, G.D. Characterization of the role of the stimulatory magnesium of Escherichia coli porphobilinogen synthase. Biochemistry 34 (1995) 244–251. [PMID: 7819203]
6.	Warren, M.J., Cooper, J.B., Wood, S.P. and Shoolingin-Jordan, P.M. Lead poisoning, haem synthesis and 5-aminolaevulinic acid dehydratase. Trends Biochem. Sci. 23 (1998) 217–221. [DOI] [PMID: 9644976]
7.	Jaffe, E.K. and Lawrence, S.H. Allostery and the dynamic oligomerization of porphobilinogen synthase. Arch. Biochem. Biophys. 519 (2012) 144–153. [DOI] [PMID: 22037356]
8.	Tian, B.X., Erdtman, E. and Eriksson, L.A. Catalytic mechanism of porphobilinogen synthase: the chemical step revisited by QM/MM calculations. J. Phys. Chem. B 116 (2012) 12105–12112. [DOI] [PMID: 22974111]

[EC 4.2.1.24 created 1961]