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PROSITE documentation PDOC00415

Polygalacturonase active site


Polygalacturonase (EC (PG) (pectinase) [1,2] catalyzes the random hydrolysis of 1,4-α-D-galactosiduronic linkages in pectate and other galacturonans. In fruit, polygalacturonase plays an important role in cell wall metabolism during ripening. In plant bacterial pathogens such as Erwinia carotovora or Pseudomonas solanacearum and fungal pathogens such as Aspergillus niger, polygalacturonase is involved in maceration and soft-rotting of plant tissue.

Exo-poly-α-D-galacturonosidase (EC (exoPG) [3] hydrolyzes peptic acid from the non-reducing end, releasing digalacturonate.

Prokaryotic, eukaryotic PG and exoPG share a few regions of sequence similarity. We selected the best conserved of these regions, which is centered on a conserved histidine most probably involved in the catalytic mechanism [4].


These proteins belong to family 28 in the classification of glycosyl hydrolases [5,E1].

Last update:

May 2004 / Text revised.

Technical section

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

POLYGALACTURONASE, PS00502; Polygalacturonase active site  (PATTERN)


1AuthorsRuttowski E. Labitzke R. Khanh N.Q. Loeffler F. Gottschalk M. Jany K.-D.
SourceBiochim. Biophys. Acta 1087:104-106(1990).

2AuthorsHuang J.H. Schell M.A.
TitleDNA sequence analysis of pglA and mechanism of export of its polygalacturonase product from Pseudomonas solanacearum.
SourceJ. Bacteriol. 172:3879-3887(1990).
PubMed ID2193922

3AuthorsHe S.Y. Collmer A.
TitleMolecular cloning, nucleotide sequence, and marker exchange mutagenesis of the exo-poly-alpha-D-galacturonosidase-encoding pehX gene of Erwinia chrysanthemi EC16.
SourceJ. Bacteriol. 172:4988-4995(1990).
PubMed ID2168372

4AuthorsBussink H.J.D. Buxton F.P. Visser J.
TitleExpression and sequence comparison of the Aspergillus niger and Aspergillus tubigensis genes encoding polygalacturonase II.
SourceCurr. Genet. 19:467-474(1991).
PubMed ID1878999

5AuthorsHenrissat B.
TitleA classification of glycosyl hydrolases based on amino acid sequence similarities.
SourceBiochem. J. 280:309-316(1991).
PubMed ID1747104


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