4-alpha-glucanotransferase | |||||||||
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Identifiers | |||||||||
EC no. | 2.4.1.25 | ||||||||
CAS no. | 9032-09-1 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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In enzymology, a 4-alpha-glucanotransferase (EC 2.4.1.25) is an enzyme that catalyzes a chemical reaction that transfers a segment of a 1,4-alpha-D-glucan to a new position in an acceptor carbohydrate, which may be glucose or a 1,4-alpha-D-glucan.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is 1,4-alpha-D-glucan:1,4-alpha-D-glucan 4-alpha-D-glycosyltransferase. Other names in common use include disproportionating enzyme, dextrin glycosyltransferase, D-enzyme, debranching enzyme maltodextrin glycosyltransferase, amylomaltase, and dextrin transglycosylase. This enzyme participates in starch and sucrose metabolism in plants. [1] [2] Studies of the enzyme from potato led to the discovery of cycloamylose. [3]
As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes 1CWY, 1ESW, 1FP8, 1FP9, 1K1W, 1K1X, 1K1Y, 1LWH, 1LWJ, 1TZ7, 1X1N, 2OWC, 2OWW, and 2OWX.
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, and is contained in large amounts in staple foods such as wheat, potatoes, maize (corn), rice, and cassava (manioc).
Cycloamyloses are cyclic α-1,4 linked glucans comprising dozens or hundreds of glucose units. Chemically they are similar to the much smaller cyclodextrins, which are typically composed of 6, 7 or 8 glucose units.
Isomaltase is an enzyme that breaks the bonds linking saccharides, which cannot be broken by amylase or maltase. It digests polysaccharides at the alpha 1-6 linkages. Its substrate, alpha-limit dextrin, is a product of amylopectin digestion that retains its 1-6 linkage. The product of the enzymatic digestion of alpha-limit dextrin by isomaltase is maltose.
1,4-alpha-glucan-branching enzyme, also known as brancher enzyme or glycogen-branching enzyme is an enzyme that in humans is encoded by the GBE1 gene.
β-Amylase is an enzyme with the systematic name 4-α-D-glucan maltohydrolase. It catalyses the following reaction:
In enzymology, a 1,4-alpha-glucan 6-alpha-glucosyltransferase is an enzyme that catalyzes the chemical reaction that transfers an alpha-D-glucosyl residue in a 1,4-alpha-D-glucan to the primary hydroxyl group of glucose or 1,4-alpha-D-glucan.
In enzymology, an amylosucrase is an enzyme that catalyzes the chemical reaction
In enzymology, a cellobiose phosphorylase is an enzyme that catalyzes the chemical reaction
In enzymology, a cellulose synthase (GDP-forming) is an enzyme that catalyzes the chemical reaction
In enzymology, a dextransucrase is an enzyme that catalyzes the chemical reaction
In enzymology, a dextrin dextranase is an enzyme that catalyzes the chemical reaction
In enzymology, an alternansucrase is an enzyme that catalyzes a chemical reaction that transfers an alpha-D-glucosyl residue from sucrose alternately to the 6- and 3-positions of the non-reducing terminal residue of an alpha-D-glucan, thereby creating a glucan with alternating alpha-1,6- and alpha-1,3-bonds. The name "alternan" was coined in 1982 for the glucan based on its alternating linkage structure.
In enzymology, a cyclomaltodextrin glucanotransferase is an enzyme that catalyzes the chemical reaction of cyclizing part of a 1,4-alpha-D-glucan molecule through the formation of a 1,4-alpha-D-glucosidic bond. They are bacterial enzymes belonging to the same family of the α-amylase specifically known as glycosyl-hydrolase family 13. This peculiar enzyme is capable of catalyzing more than one reaction with the most important being the synthesis of non-reducing cyclic dextrins known as cyclodextrins starting from starch, amylose, and other polysaccharides.
In enzymology, a NDP-glucose—starch glucosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a starch synthase is an enzyme that catalyzes the chemical reaction
In enzymology, a sucrose-1,6-alpha-glucan 3(6)-alpha-glucosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a xyloglucan:xyloglucosyl transferase (EC 2.4.1.207) is an enzyme that catalyzes the chemical reaction in which a beta-(1,4) bond in the backbone of a xyloglucan in broken; the xyloglucanyl segment is then transferred to the O4 of the non-reducing terminal glucose residue of either xyloglucan or an oligosaccharide thereof.
In enzymology, an oligosaccharide 4-alpha-D-glucosyltransferase is an enzyme that catalyzes the chemical reaction in which the non-reducing terminal alpha-D-glucose residue is transferred from a 1,4-alpha-D-glucan to the 4-position of an alpha-D-glucan. This enzyme is useful in hydrolyzing oligosaccharides.
α-Glucans (alpha-glucans) are polysaccharides of D-glucose monomers linked with glycosidic bonds of the alpha form. α-Glucans use cofactors in a cofactor site in order to activate a glucan phosphorylase enzyme. This enzyme causes a reaction that transfers a glucosyl portion between orthophosphate and α-I,4-glucan. The position of the cofactors to the active sites on the enzyme are critical to the overall reaction rate thus, any alteration to the cofactor site leads to the disruption of the glucan binding site.
Steven M. Smith is Emeritus Professor of Plant Genetics and Biochemistry at the University of Tasmania in Australia and Chief Investigator in the Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture.
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