The Mode of Action of Endo oc - 1 , 4 on Galactosaminooligosaccharides

The mode of action of the endo ct-1,4 polygalactosaminidase from Pseudomonas sp. 881 on galactesaminooligosaccharides (GOSs) was studied. The enzyme could hydrolyze ct-1,4 polygalactosamine to GOSs by the endo-split manner. Tetraose and longer GOSs were hydrolyzed to galactosaminobiose and ga]actosaminotriose as the final products. Galactosaminomonomer (galactosamine) cou]d not be produced as an enzymatic product. From the dependency of kinetic parameters on the chain lengths of the substrates, it was suggested that the enzyme has 8 subsites. A catalytic site of the enzyme is located between the third and the fourth sites from the non-reducing end, since the main product from GOSs was galactosaminotriose, and galactosaminotetraitol remained in the hydrolyzate of galactosaminoheptaitol digestion. The enzyme showed transglycosylating activity on GOS4.