Wiktionary
n. (context enzyme English) Any enzyme that catalyses the hydrolysis of polymeric galacturonic acids and similar carbohydrates
Wikipedia
Polygalacturonase , also known as pectin depolymerase, PG, pectolase, pectin hydrolase, and poly-alpha-1,4-galacturonide glycanohydrolase, is an enzyme that hydrolyzes the alpha-1,4 glycosidic bonds between galacturonic acid residues. Polygalacturonan, whose major component is galacturonic acid, is a significant carbohydrate component of the pectin network that comprises plant cell walls. Therefore, the activity of the endogenous plant PGs works to soften and sweeten fruit during the ripening process. Similarly, phytopathogens use PGs as a means to weaken the pectin network, so that digestive enzymes can be excreted into the plant host to acquire nutrients.
Usage examples of "polygalacturonase".
Apples lack polygalacturonase, which is why they remain crisp until they degenerate and decaythe stage beyond ripeness when a fruit becomes subject to microbial attack and rot.