THE GLYCOPROTEIN CHARACTER OF MULTIPLE FORMS OF ASPERGILLUS POLYGALACTURONASE

Comparisons of known primary structures of polygalacturonases show tha t extent and localization of potential N-glycosylation sites differ. S ome sites are similar in position and adjacent to strictly conserved r esidues at the potential active site. The presence of N-acetylglucosam ine and mannose in the molecules of two homogeneous, major Aspergillus sp. polygalacturonase forms was confirmed by IR spectroscopy. The pur ification method, based on interaction of the carbohydrate part with c oncanavalin A immobilized on chlorotriazine bead cellulose, was optimi zed. Deglycosylation with N-glycosidase F under denaturating and nonde naturating conditions led to molecular mass decreases followed by comp lete inactivation of the polygalacturonase enzyme activity. These resu lts show the importance of glycosylation in these protein forms, while the comparative patterns establish both variability and some similari ties in overall glycosylation architectures.