Purification and properties of endo-1, 3-alpha-D-glucanase from Pseudomonas

An endo-1, 3-alpha-D-glucanase (EC 3.2.1.59) was purified from cell-free culture supernatants of Pseudomonas NRRL-B-12324. The enzyme was purified 8.7-fold to a specific activity of 78.1 U/mg of protein. The enzyme was inducible and had an isoelectric point of 4.6 and a Km of 80.0 mM in terms of anhydroglucose units. Two distinct peaks of activity were resolved by gel filtration with two different supporting media, whereas only one peak of activity was resolved by isoelectricfocusing. The two peaks were assigned molecular weight values of 67,400 and 279,000. The pH optimum was near 5.0 and the temperature optimum was near 56 degrees C. Additional gel filtration data indicated that the enzyme functions as an endohydrolase.