HEXOSAMINIDASE IN TRICHINELLA-SPIRALIS IS A SINGLE PROTEIN WITH ALPHA-SUBUNIT AND BETA-SUBUNIT CATALYTIC ACTIVITIES

beta-N-acetylhexosaminidase is expressed as a single protein in Trichi nella spiralis and has catalytic properties similar to the alpha- and beta-subunits of human and mouse isoenzymes A and B. It can hydrolyze the artificial substrates, 4-methylumbelliferyl-beta-D-glucosamine and 4-methylumbelliferyl-beta-D-glucosamine-6-sulphate which are respecti vely hydrolyzed by the beta- and alpha-subunits. The enzyme is thermos table, has a basic isoelectric point, and thus is similar to the B iso enzyme. Northern blotting experiments indicate that the enzyme is enco ded by a single gene. Hexosaminidase from Trichinella spiralis shows t hat the substrate specificities of alpha- and beta-subunits precede th e duplication of their genes.