Glycoside hydrolase, family 28 (IPR000743)

Short name: Glyco_hydro_28

Overlapping homologous superfamilies

Family relationships



O-Glycosyl hydrolases (EC:3.2.1.) are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [PMID: 7624375, PMID: 8535779]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.

Glycoside hydrolase family 28 GH28 comprises enzymes with several known activities; polygalacturonase (EC:; exo-polygalacturonase (EC:; exo-polygalacturonase (EC:; rhamnogalacturonase (EC not defined).

Polygalacturonase (PG) (pectinase) [PMID: 2400785, PMID: 2193922] catalyses the random hydrolysis of 1,4-alpha-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 Ralstonia solanacearum (Pseudomonas solanacearum) and fungal pathogens such as Aspergillus niger, polygalacturonase is involved in maceration and soft-rotting of plant tissue. Exo-poly-alpha-D-galacturonosidase (EC: (exoPG) [PMID: 2168372] hydrolyses peptic acid from the non-reducing end, releasing digalacturonate. PG and exoPG share a few regions of sequence similarity, and belong to family 28 of the glycosyl hydrolases.

GO terms

Biological Process

GO:0005975 carbohydrate metabolic process

Molecular Function

GO:0004650 polygalacturonase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns