[A stepwise method of evaluating sugar substitutes--a preliminary study using enzymes. 2. Beta-fructosidase from...

Area of Science:

• Enzymology
• Carbohydrate Chemistry
• Biochemistry

Background:

• Beta-fructosidase (invertase) from yeast exhibits high substrate specificity.
• Understanding enzyme-substrate interactions is crucial for evaluating sugar substitutes.
• Glycosidic bonds between glucose and fructose influence enzyme activity and potential cariogenicity.

Purpose of the Study:

• To investigate the substrate properties of various D-glucosylfructoses for yeast beta-fructosidase.
• To determine the inhibitory effects of specific disaccharides on beta-fructosidase activity.
• To assess the predictive power of beta-fructosidase assays for the cariological potential of sugar substitutes.

Main Methods:

• Enzyme kinetic assays using yeast beta-fructosidase.
• Testing of sucrose, leucrose, and isomaltulose (Palatinose) as substrates and inhibitors.
• Analysis of enzyme inhibition patterns (non-competitive and uncompetitive).

Main Results:

• None of the tested D-glucosylfructoses, except sucrose, acted as substrates for yeast beta-fructosidase.
• Leucrose demonstrated non-competitive inhibition of beta-fructosidase.
• Isomaltulose (Palatinose) exhibited uncompetitive inhibition of beta-fructosidase.

Conclusions:

• Yeast beta-fructosidase displays strict substrate specificity, primarily acting on sucrose.
• Leucrose and isomaltulose function as inhibitors, not substrates, indicating their different metabolic fates.
• The substrate specificity of invertase allows for predicting the cariological impact of novel sugar substitutes.