|Formulation:||In 3.2 M ammonium sulphate|
|Stability:||> 4 years at 4oC|
|Synonyms:||isoamylase; glycogen 6-alpha-D-glucanohydrolase|
|Concentration:||Supplied at ~ 500 U/mL|
|Expression:||Purified from Pseudomonas sp.|
|Specificity:||Hydrolysis of (1,6)-α-D-glucosidic branch linkages in glycogen, amylopectin and their β-limit dextrins.|
|Specific Activity:||~ 240 U/mg (40oC, pH 4.0 on oyster glycogen) (equivalent to 16 MU Sigma Units/mg)|
|Unit Definition:||One unit of isoamylase activity is the amount of enzyme required to release one µmole of D-glucose reducing sugar equivalent in the presence of oyster glycogen per min at pH 4.0 and 40oC.|
|Application examples:||Applications in carbohydrate research and in the food and feeds, and cereals industry.|
|Method recognition:||ISO Standard 6647-1:2015|
High purity Isoamylase HP (Glycogen 6-glucanohydrolase) for use in research, biochemical enzyme assays and in vitro diagnostic analysis. Suitable for use in ISO Standard 6647-1:2015.
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Validation of Methods
A simplified method of determining the internal structure of amylopectin from barley starch without amylopectin isolation.
Zhao, X., Andersson, M. & Andersson, R. (2020). Carbohydrate Polymers, 117503.
To determine the internal structure of barley starch without amylopectin isolation, whole starch was hydrolyzed using β-amylase to remove the linear amylose and obtain β-limit dextrins (β-LDs). The β-LDs were treated with extensive α-amylase to prepare α-limit dextrins (α-LDs), and the α-LDs were further hydrolyzed with β-amylase into building blocks. The chain-length distribution of β-LD and building block composition were analyzed by size-exclusion chromatography and anion-exchange chromatography. The internal structure of the barley whole starches had similar pattern to barley amylopectins analyzed by conventional methods. The starch of barley amo1-mutated varieties contained more short internal B-chains and less long internal B-chains than that of other varieties. The starch from amo1-mutated varieties had more large building blocks than that from waxy varieties. The simplified method presented in this study can effectively characterize starch internal structure that relates to physicochemical properties of starch, although some details of amylopectin structure are not assessable.Hide Abstract
Structural characterization of mixed-linkage α-glucans produced by mutants of Lactobacillus reuteri TMW 1.106 dextransucrase.
Münkel, F., Fischer, A., & Wefers, D. (2020). Carbohydrate Polymers, 231, 115697.
Dextrans and other bacterial α-glucans are versatile and structurally diverse polysaccharides which can be enzymatically synthesized by using glucansucrases. By substituting certain amino acids in the active site of these enzymes, the structure of the synthesized polysaccharides can be modified. In this study, such amino acid substitutions were applied (single and combined) to the dextransucrase from Lactobacillus reuteri TMW 1.106 and the structures of the synthesized polysaccharides were subsequently characterized in detail. Besides methylation analysis, α-glucans were hydrolyzed by several glycoside hydrolases and the liberated oligosaccharides were identified by comparison to standard compounds or by isolation and NMR spectroscopic characterization. Furthermore, two-dimensional NMR spectroscopy was used to analyze the untreated polysaccharides. The results demonstrated that structurally different α-glucans were formed, for example different highly O4-branched dextrans or several reuteran-like polymers with varying fine structures. Consequently, mutant Lactobacillus reuteri TMW 1.106 dextransucrases can be used to form structurally unique polysaccharides.Hide Abstract