Fructofuranosyl-enzyme

Sucralose (l,6-dichloro-l,6-dideoxy- 5-fructofuranosyl-4-chloro-a-D-galactopyra- noside) is a nonnutritive sweetener based on sucrose. It is selectively chlorinated and the glycoside link between the two rings is resistant to hydrolysis by acid or enzymes, so it is not metabohzed. It has 400 to 800 times the sweetness of sucrose, is very soluble in water, and is stable in heat. It can be used in food products that are baked or fried. 

D-Fructans are hydrolyzed by two D-fructofuranosidases designated hydrolase A and B.203-205 Enzymic hydrolysis breaks only the ft-D-(2 — l)-linkage between a terminal D-fructofuranosyl group and its adjacent, D-fructofuranosyl chain unit as shown in equation 4. 

Leuconostoc species may be satisfactorily cultured on a variety of carbohydrates, but, for the production of dextransucrases, sucrose must be included in the nutrient medium indeed, it has been suggested that the enzyme-induction process may be triggered by the n-fructofuranosyl group of the sucrose molecule. In consequence of this condition, preparations of dextransucrases from Leuconostoc species have contained various proportions of dextran that could not be removed by any fractionation procedures available. The presence of this tenaciously boimd dextran, once regarded as an integral part of the dextransucrase molecule, has presented a major obstacle to further study of the enzyme. Stacey and associates attempted to produce a dextran-free enzyme by growing L. mesenteroides NRRL B-1375 on a sucrose mediiun contain-... 

Hestrin, Feingold, and Avigad (195a) found that the levansucrase enzyme system of Aerohacter levanicum which utilizes the D-fructose moiety of sucrose, forming a polysaccharide (levan) and D-glucose, possesses a complementary property of catalyzing the reversible transfer of the D-fruc-tosyl unit of jS-D-fructofuranosyl aldosides of different configurations to the anomeric carbon position of an aldose. 

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