Three polygalacturonases constitutively synthesized by Aspergillus alliaceus.

Of three molecular forms of polygalacturonases synthesized by Aspergillus alliaceus on glucose media, two were exopolygalacturonases (exoPG1 and exoPG2) and one was an endopolygalacturonase (endoPG). Low-methoxylated beet pectin was the preferred substrate for the endoPG and exoPG2 whereas pectic acid was the optimal substrate for exoPG1. The highest activities of endoPG, exoPG1 and exoPG2 were at pH 5.5, 3.5, and 6.0 and at 35, 45 to 50 and 35°C, respectively. Disks of potato-tuber tissue were macerated by endoPG, but not by exoPG1 or exoPG2.