Characterization of transfructosylating activity enzyme from tubers of tropical Jerusalem artichoke (Helianthus tuberosus L.) for production of fructooligosaccharides

Prakobpran, P.; Keayarsa, S.; Wichienchot, S.; Ngampanya, B.; Jaturapiree, P.

Characterization of transfructosylating activity enzyme from tubers of tropical Jerusalem artichoke (Helianthus tuberosus L.) for production of fructooligosaccharides

2016

Prakobpran, P. | Keayarsa, S. | Wichienchot, S. | Ngampanya, B. | Jaturapiree, P.

A crude extract from tubers of tropical Jerusalem artichoke (Helianthus tuberosus L.) with high transfructosylating activity was purified by two chromatographic steps (anion exchangeand affinity chromatography). Gel filtration under native conditions revealed that the purifiedenzyme had molecular mass approximately 75 kDa whereas SDS-PAGE indicated it was dimeric protein with molecular mass approximately 66 and 25 kDa. The optimal pH and temperatureof purified enzyme were 5.4 and 35˚C, respectively. The activity of enzyme was enhanced bypyridoxal-HCl, while KI had an effect to inhibit its activity. Using sucrose as substrate, the Km values for transfructosylating activity were rather high. This enzyme might be sucrose:sucrose fructosyltransferase (SST) because it can use sucrose as the smallest donor substrate in synthesis of fructooligosaccharides (FOS) with degree of polymerization (DP) less than 5as major products. When 0.26 U of purified enzyme was incubated with 0.46 M sucrose as substrate at pH 5.4 and 35ºC for 144 h, about 54.46% short chain fructooligosaccharides (scFOS,DP<5) was produced. Additionally, the scFOS showed growth promoting to Bifidobacteriumsp. indicated it has prebiotic property by supporting the growth of probiotics. It might be an alternative means for biosynthesis of scFOS by SST from plant for applications in functionalfoods and nutraceuticals industry.

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