Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

porphobilinogen synthase

Name from literature

delta-aminolevulinic acid synthase

Pathway from literature

heme biosynthesis

Pathway from KEGG

Metabolism of Cofactors and Vitamins; Porphyrin and chlorophyll metabolism; map00860


Human (9606)

Genome localization

9q33.1[210 ],


The fungal enzyme is a metalloprotein.

Rate-limiting Description

"The activities of delta-aminolevulinic acid synthase, a rate-limiting enzyme in the heme biosynthesis, and porphobilinogen synthase in the liver of rhIL-1beta-induced fevered rat were significantly lower than those in the control, whereas the activity of heme oxygenase, a key enzyme in the heme-degradative pathway, markedly increased in the fevered rat." (10634305)

"Ethanol suppresses the activity of porphobilinogen synthase (synonym: delta-aminolevulinic acid dehydratase), uroporphyrinogen decarboxylase, coproporphyrinogen oxidase and ferrochelatase, whereas it induces the first and rate-limiting enzyme in the pathway, delta-aminolevulinic acid synthase and also porphobilinogen deaminase." (10787385)

Regulatory Information

Regulatory type


transcriptional level;

"delta-Aminolevulinate dehydratase: induced expression and regional assignment of the human gene to chromosome 9q13----qter." (3997152)

key enzyme;

"Delta-aminolaevulinic acid dehydrogenase is a key enzyme in porphyrin synthesis which catalyses the formation of porphobilinogens from two molecules of delta-aminolaevulinic acid." (7436670)



Gene ontology

Gene ontology

GO:0008270 (F) zinc ion binding [P13716 ];
GO:0006783 (P) heme biosynthetic process [P13716 ];
GO:0004655 (F) porphobilinogen synthase activity [A8K375, P13716, Q6ZMU0 ];
GO:0005829 (C) cytosol [P13716 ];
GO:0006779 (P) porphyrin biosynthetic process [A8K375, Q6ZMU0 ];
GO:0046872 (F) metal ion binding [A8K375, Q6ZMU0 ];

Disease relevance


Defects in ALAD are the cause of acute hepatic porphyria (AHP) [MIM:125270]. AHP is a form of porphyria. Porphyrias are inherited defects in the biosynthesis of heme. AHP is characterized by attacks of gastrointestinal disturbances, abdominal colic, paralysis, and peripheral neuropathy. Most attacks are precipitated by drugs, alcohol, caloric deprivation, infections, or endocrine factors [P13716 ];



A8K375; P13716; Q6ZMU0

Entrez Gene




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  Last Modified: 2009-03-24  
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