The effect of several metal ions on enzymatic activity of ß-fructofuranosidase from schwanniomyces occidentalis

Trabajo presentado en el ANQUE.ICCE.BIOTEC - Congress on Chemistry, Chemical Engineering and Biotechnology, celebrado en Madrid del 01 al 04 de julio de 2014.
β-fructofuranosidase from the non-conventional yeast Schwanniomyces occidentalis (Ffase) is a robust extracellular enzyme that catalyse the hydrolysis of several glycosidic subtrates with β-(2 → 1)-linked fructose moieties, such as sucrose, raffinose, and inulin [1]. The Ffase three dimentional structure has been solved as an homodimer of 160 KDa arranged like any other glycosyl-hydrolase (GH) enzyme included in family 32 (GH32); except that supplementary βsandwich domain of each molecular subunit is involved in substrate binding [2,3]. Interestingly, at high sucrose concentrations, this enzyme display varying degrees of fructosyltransferase activity by cleaving the β-(2 → 1) linkage, releasing glucose, and transferring a fructose unit onto a sucrose acceptor molecule. This results in an efficient production of two short-chain fructooligosaccharides (FOS), 6-kestose and 1-kestose, in a 3.5:1 ratio [1]. Both of them are considered as healthpromoting food ingredients because of their prebiotic properties [1]. In this work, we analysed in detail the hydrolytic and transfructosylating enzyme activity beneath the influence of different binary salts, containing, among others, Na+ ,Ca2+,Mg2+ and Fe3+. As it was expected from previous reports based on other GH32 yeast enzymes, all of these metal ions seem to affect significantly Ffase activity from a certain concentration on; albeit in a different way, despite the fact that all of them were supposed to be activators.