To study the role of carbohydrate on the properties of the external invertase of Saccharomyces cerevisiae, about 90% of the carbohydrate associated with this glycoprotein was removed by endo-beta-N-acetylglucosaminidase H. Although the catalytic and physical properties of the carbohydrate-depleted (CHO(-)) and the carbohydrate-containing (CHO(+)) enzyme did not differ significantly in a number of parameters tested, the CHO(-) form was much less stable to multiple freezethaw treatment, incubation at 5O C, acidic conditions, and trypsin digestion. In addition, following guanidine hydrochloride inactivation of CHO(+) and CHO(-) enzyme, a marked difference in the recovery of enzyme activity was noted on removal of this denaturant; 76% of the original activity was restored for native invertase, but only 34% for CHO(-) invertase. Circular dichroism studies of the renatured forms and their parent molecules revealed significant differences in ellipticity at 232 and 293 nm with renatured CHO(-) invertase. Similarly, tryptophan fluorescence studies showed a significant reduction in fluorescence in the renatured CHO(-) enzyme. Incubation of the released oligosaccharides with this form of the enzyme during or after guanidine hydrochloride treatment did not increase the amount of enzyme activity recovered. From these studies, it would appear that the covalently bound carbohydrate of yeast invertase plays a role in promoting the folding of the enzyme protein to its most stable conformation.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|