galacturonan 1,4-alpha-galacturonidase; exo-polygalacturonase; poly(galacturonate) hydrolase (ambiguous); exo-D-galacturonase; exo-D-galacturonanase; exopoly-D-galacturonase; poly(1,4-alpha-D-galacturonide) galacturonohydrolase (ambiguous); pgaA (ge • • •