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PROSITE documentation PDOC00153

Delta-aminolevulinic acid dehydratase active site


Delta-aminolevulinic acid dehydratase (EC (ALAD) [1] catalyzes the second step in the biosynthesis of heme, the condensation of two molecules of 5-aminolevulinate to form porphobilinogen. The enzyme is an oligomer composed of eight identical subunits. Each of the subunits binds an atom of zinc or of magnesium (in plants). A lysine has been implicated in the catalytic mechanism [2]. The sequence of the region in the vicinity of the active site residue is conserved in ALAD from various prokaryotic and eukaryotic species.

Last update:

November 1995 / Pattern and text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

D_ALA_DEHYDRATASE, PS00169; Delta-aminolevulinic acid dehydratase active site  (PATTERN)


1AuthorsLi J.-M., Russell C.S., Cosloy S.D.
TitleThe structure of the Escherichia coli hemB gene.
SourceGene 75:177-184(1989).
PubMed ID2656410

2AuthorsGibbs P.N.B., Jordan P.M.
TitleIdentification of lysine at the active site of human 5-aminolaevulinate dehydratase.
SourceBiochem. J. 236:447-451(1986).
PubMed ID3092810

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