Determination of fructan exohydrolase activity in the crude extracts of plants|
Tatjana Krivorotova, Jolanta Sereikaite
Background: The roots of chicory and the tubers of Jerusalem artichoke are used for the production of inulin.
However, a quality of tubers and roots, i.e. the content of inulin, monosaccarides and disaccharides, depends on
the activity of enzymes implicated in the metabolism of inulin. The knowledge on the changes of activities of
inulin synthesizing and degrading enzymes is limited during plant sprouting, growth and dormancy. It happens
due to complicated measurements of the product of enzymatic reaction in the presence of crude plant extract.
Fructan exohydrolase (β-D-fructan fructohydrolase, FEH, EC 18.104.22.168) is an enzyme responsible for the hydrolysis
of fructans in plants. For fructose as the reaction product measurement, a high-performance liquid
chromatography is usually used. The aim of the study was to choose a simple and suitable method for FEH
activity determination and the measurement of fructose in the presence of plant extracts.
Results: Two chemical methods, i.e. copper(II)–neocuproine and 3,5-dinitrosalicylic acid, and the enzymatic one
based on the reactions catalyzed by hexokinase, phosphoglucose isomerase and glucose-6-phosphate
dehydrogenase were used. Enzymatic method was found to be suitable for FEH activity determination in plant
extracts, and on the contrary to chemical methods no interference effects of compounds from crude plant
extracts were observed.
Conclusion: Enzymatic method is applicable for the routine analysis and will allow performing the investigations
without special equipment on the inulin degrading enzyme in biotechnologically important crops.
3,5-Dinitrosalicylic acid; Copper(II)–neocuproine; Enzymatic method; Fructose determination