Reaction: [(1→4)-α-D-galacturonide]n + H2O = [(1→4)-α-D-galacturonide]n-1 + D-galacturonate
Other name(s): exo-polygalacturonase; poly(galacturonate) hydrolase (ambiguous); exo-D-galacturonase; exo-D-galacturonanase; exopoly-D-galacturonase; poly(1,4-α-D-galacturonide) galacturonohydrolase (ambiguous); pgaA (gene name); pgaB (gene name); pgaC (gene name); pgaD (gene name); pgaE (gene name); pgaI (gene name); pgaII (gene name); poly[(1→4)-α-D-galacturonide] galacturonohydrolase; galacturan 1,4-α-galacturonidase (incorrect)
Systematic name: poly[(1→4)-α-D-galacturonide] non-reducing-end galacturonohydrolase
Comments: The enzyme hydrolyses the first glycosidic bond from the non-reducing end of the substrate. It is specific for saturated oligomers of D-homogalacturonan, and is unable to degrade unsaturated substrates or methyl-esterified substrates.
Links to other databases: BRENDA, EXPASY, ExplorEnz, KEGG, MetaCyc, PDB, CAS registry number: 9045-35-6
References:
1. Hasegawa, H. and Nagel, C.W. Isolation of an oligogalacturonate hydrolase from a Bacillus species. Arch. Biochem. Biophys. 124 (1968) 513-520. [PMID: 5661621]
2. Kluskens, L.D., van Alebeek, G.J., Walther, J., Voragen, A.G., de Vos, W.M. and van der Oost, J. Characterization and mode of action of an exopolygalacturonase from the hyperthermophilic bacterium Thermotoga maritima. FEBS J. 272 (2005) 5464-5473. [PMID: 16262687]
3. Martens-Uzunova, E.S., Zandleven, J.S., Benen, J.A., Awad, H., Kools, H.J., Beldman, G., Voragen, A.G., Van den Berg, J.A. and Schaap, P.J. A new group of exo-acting family 28 glycoside hydrolases of Aspergillus niger that are involved in pectin degradation. Biochem. J. 400 (2006) 43-52. [PMID: 16822232]
4. Pijning, T., van Pouderoyen, G., Kluskens, L., van der Oost, J. and Dijkstra, B.W. The crystal structure of a hyperthermoactive exopolygalacturonase from Thermotoga maritima reveals a unique tetramer. FEBS Lett. 583 (2009) 3665-3670. [PMID: 19854184]