The Mode of Action of Endo α-1,4 Polygalactosaminidase from Pseudomonas sp. 881 on Galactosaminooligosaccharides.

The mode of action of the endo (α-1,4 polygalactosaminidase from Pseudomonas sp. 881 on galactosaminooligosaccharides (GOSs) was studied. The enzyme could hydrolyze (α-1,4 polygalactosamine to GOSs by the endo-split manner. Tetraose and longer GOSs were hydrolyzed to galactosaminobiose and galactosaminotriose as the final products. Galactosaminomonomer (galactosamine) could 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.