Polygalacturonase is a pectinase: an enzyme that degrades pectin.
PGs hydrolyze the O-glycosyl bonds in pectin’s polygalacturonan network, resulting in alpha-1,4-polygalacturonic residues.
The rate of hydrolysis is dependent on polysaccharide chain length.
Low rates of hydrolysis are associated with very short chains (e.g. digalacturonic acid) and very long chains.

Exo- vs Endo-polygalacturonases
Exo- and Endo-PGs utilize different hydrolytic modes of action.
Endo-PGs hydrolyze in a random fashion along the polygalacturonan network.
This method results in oligogalacturonides.
Exo-PGs hydrolyze at the non-reducing end of the polymer, generating a monosaccharide galacturonic acid.
Occasionally, organisms employ both methods.
In addition to different modes of action, PG polymorphism allows fungal PGs to more effectively degrade a wider range of plant tissues.
PG variety in optimal pH, substrate specificity, and other factors are likely helpful for phytopathogenic organisms like fungi.
Polygalacturonase is a pectinase: an enzyme that degrades pectin. PGs hydrolyze the O-glycosyl bonds in pectin’s polygalacturonan network, resulting in alpha-1,4-polygalacturonic residues. The rate of hydrolysis is dependent on polysaccharide chain length. Low rates of hydrolysis are associated with very short chains (e.g. digalacturonic acid) and very long chains.
Exo- vs Endo-polygalacturonases
Exo- and Endo-PGs utilize different hydrolytic modes of action. Endo-PGs hydrolyze in a random fashion along the polygalacturonan network. This method results in oligogalacturonides. Exo-PGs hydrolyze at the non-reducing end of the polymer, generating a monosaccharide galacturonic acid. Occasionally, organisms employ both methods. In addition to different modes of action, PG polymorphism allows fungal PGs to more effectively degrade a wider range of plant tissues. PG variety in optimal pH, substrate specificity, and other factors are likely helpful for phytopathogenic organisms like fungi.
Polygalacturonase