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|Stability:||> 10 years under recommended storage conditions|
|Substrate For (Enzyme):||endo-1,6-α-Dextrinase, oligo-1,6-α-Glucosidase, α-Glucosidase|
High purity isomaltose for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
The influence of α-1, 4-glucan substrates on 4, 6-α-D-glucanotransferase reaction dynamics during isomalto/malto-polysaccharide synthesis.
Klostermann, C. E., van der Zaal, P. H., Schols, H. A., Buwalda, P. L. & Bitter, J. H. (2021). International Journal of Biological Macromolecules, 181, 762-768.
Starch-based isomalto/malto-polysaccharides (IMMPs) are soluble dietary fibres produced by the incubation of α-(1 → 4) linked glucans with the 4,6-α-glucanotransferase (GTFB) enzyme. In this study, we investigated the reaction dynamics of the GTFB enzyme by using isoamylase debranched starches as simplified linear substrates. Modification of α-glucans by GTFB was investigated over time and analysed with 1H NMR, HPSEC, HPAEC combined with glucose release measurements. We demonstrate that GTFB modification of linear substrates followed a substrate/acceptor model, in which α-(1 → 4) linked glucans DP ≥ 6 functioned as donor substrate, and α-(1 → 4) linked malto-oligomers DP < 6 functioned as acceptor. The presence of α-(1 → 4) linked malto-oligomers DP < 6 resulted in higher GTFB transferase activity, while their absence resulted in higher GTFB hydrolytic activity. The information obtained in this study provides a better insight into GTFB reaction dynamics and will be useful for α-glucan selection for the targeted synthesis of IMMPs in the future.Hide Abstract
Sequence analysis and biochemical properties of an acidophilic and hyperthermophilic amylopullulanase from Thermofilum pendens.
Li, X., Zhao, J., Fu, J., Pan, Y., & Li, D. (2018). International Journal of Biological Macromolecules, 114, 235-243.
The acidophilic and thermophilic pullulanases have many potential applications in the processes of starch liquefaction and saccharification. In this study, a gene encoding an amylopullulanase from Thermofilum pendens (TPApu) was heterologously expressed in Escherichia coli. Although TPApu possessed the same continuous GH57N_Apu domain and the succeeding α-helical region as other two amylopullulanases from Staphylothermus marinus (SMApu) and Caldivirga maquilingensis (CMApu), it only showed maximal amino acid identities of 25.7-28.7% with CMApu and SMApu. The purified TPApu appeared as a single band of SDS-PAGE with a molecular mass of 65.5 kDa and exhibited the maximal activity at pH 3.5 and 95-100°C. TPApu had the highest catalytic efficiency towards pullulan (kcat/km, 8.79 s-1 mL mg-1) and α-cyclodextrin (kcat/km, 0.36 s-1 mM-1). In the initial stages, the ring-opening reactions of γ-cyclodextrin, 6-O-glucosyl-β-cyclodextrin, 6-O-maltosyl-β-cyclodextrin and the debranching reactions of 6-O-maltooctaosyl-β-cyclodextrin were firstly catalyzed. In the subsequent reactions, a serial of maltooligosaccharides were produced. As the most acidophilic amylopullulanase among thermophilic pullulanases reported to date, TPApu preferred to debranch the DP6-12 side chains of amylopectin at pH 4.5 and 100°C.Hide Abstract