Enzymic Formation of β-D-Fructofuranosides from Sucrose: Activity and Selectivity of Inventase in Mixtures of Water and Alcohol

Abstract

Invertase-catalysed alcoholysis of sucrose in water - primary alcohol mixtures containing up to 70% organic solvent shows 5-40% alkyl β-D-fructofuranoside formation. No formation of fructosides was observed under anhydrous conditions. The kinetics of the competing reactions of water and primary alcohol as fructosyl acceptors with sucrose as fructosyl donor were studied in order to establish the scope and limitations of the method. On a molar basis, water was a relatively unreactive acceptor. 6-Kestose formation due to sucrose itself as a fructosyl acceptor was suppressed by the presence of aliphatic alcohols. The results have been explained by assuming an nonspecific non-polar binding site to be present in the enzyme cavity near the specific polar binding site for the β-D-fructofuranosyl group of the substrate.