Isomaltulose synthase

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isomaltulose synthase
Identifiers
EC no. 5.4.99.11
CAS no. 159940-49-5
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MetaCyc metabolic pathway
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In enzymology, an isomaltulose synthase (EC 5.4.99.11) is an enzyme that catalyzes the chemical reaction

sucrose 6-O-Alpha-D-Glucopyranosyl-D-Fructofuranose

Hence, this enzyme has one substrate, sucrose (table sugar), and one product, 6-O-Alpha-D-Glucopyranosyl-D-Fructofuranose (also known as isomaltulose or Palatinose). It converts the α-1,2 glycosidic linkage between glucose and fructose in sucrose into the α-1,6 glycosidic linkage between glucose and fructose in isomaltulose.

This enzyme belongs to the family of isomerases. The systematic name of this enzyme class is sucrose glucosylmutase. Other names in common use include sucrose isomerase, sucrose alpha-glucosyltransferase, and trehalulose synthase.

The isomaltulose synthase of the bacterium Protaminobacter rubrum is commonly used in the industrial production of isomaltulose. [1]

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1M53, 1ZJA, 1ZJB, 2PWD, 2PWE, 2PWF, and 2PWG.

Related Research Articles

<span class="mw-page-title-main">Disaccharide</span> Complex sugar

A disaccharide is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common examples are sucrose, lactose, and maltose.

<span class="mw-page-title-main">Starch</span> Glucose polymer used as energy store in plants

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).

<span class="mw-page-title-main">Fructose</span> Simple ketonic monosaccharide found in many plants

Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed by the gut directly into the blood of the portal vein during digestion. The liver then converts both fructose and galactose into glucose, so that dissolved glucose, known as blood sugar, is the only monosaccharide present in circulating blood.

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β-Fructofuranosidase is an enzyme that catalyzes the hydrolysis (breakdown) of the table sugar sucrose into fructose and glucose. Alternative names for β-fructofuranosidase EC 3.2.1.26 include invertase, saccharase, glucosucrase, β-fructosidase, invertin, fructosylinvertase, alkaline invertase, and acid invertase. The resulting mixture of fructose and glucose is called inverted sugar syrup. Related to invertases are sucrases. Invertases and sucrases hydrolyze sucrose to give the same mixture of glucose and fructose. Invertase is a glycoprotein that hydrolyses (cleaves) the non-reducing terminal β-fructofuranoside residues. Invertases cleave the O-C(fructose) bond, whereas the sucrases cleave the O-C(glucose) bond. Invertase cleaves the α-1,2-glycosidic bond of sucrose.

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<span class="mw-page-title-main">Isomaltulose</span> Chemical compound

Isomaltulose is a disaccharide carbohydrate composed of glucose and fructose. It is naturally present in honey and sugarcane extracts and is also produced industrially from table sugar (sucrose) and used as a sugar alternative.

<span class="mw-page-title-main">Sucrose phosphorylase</span> Class of enzymes

Sucrose phosphorylase is an important enzyme in the metabolism of sucrose and regulation of other metabolic intermediates. Sucrose phosphorylase is in the class of hexosyltransferases. More specifically it has been placed in the retaining glycoside hydrolases family although it catalyzes a transglycosidation rather than hydrolysis. Sucrose phosphorylase catalyzes the conversion of sucrose to D-fructose and α-D-glucose-1-phosphate. It has been shown in multiple experiments that the enzyme catalyzes this conversion by a double displacement mechanism.

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<span class="mw-page-title-main">Sucrose-phosphate synthase</span> Class of enzymes

Sucrose-phosphate synthase (SPS) is a plant enzyme involved in sucrose biosynthesis. Specifically, this enzyme catalyzes the transfer of a hexosyl group from uridine diphosphate glucose (UDP-glucose) to D-fructose 6-phosphate to form UDP and D-sucrose-6-phosphate. This reversible step acts as the key regulatory control point in sucrose biosynthesis, and is an excellent example of various key enzyme regulation strategies such as allosteric control and reversible phosphorylation.

<span class="mw-page-title-main">Sucrose synthase</span> Protein family

In enzymology, a sucrose synthase is an enzyme that catalyzes the chemical reaction

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<span class="mw-page-title-main">Glucansucrase</span> Enzyme

Glucansucrase is an enzyme in the glycoside hydrolase family GH70 used by lactic acid bacteria to split sucrose and use resulting glucose molecules to build long, sticky biofilm chains. These extracellular homopolysaccharides are called α-glucan polymers.

<span class="mw-page-title-main">Glycoside hydrolase family 36</span>

In molecular biology, glycoside hydrolase family 36 is a family of glycoside hydrolases.

<span class="mw-page-title-main">Xylose isomerase</span> Class of enzymes

In enzymology, a xylose isomerase is an enzyme that catalyzes the interconversion of D-xylose and D-xylulose. This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases interconverting aldoses and ketoses. The isomerase has now been observed in nearly a hundred species of bacteria. Xylose-isomerases are also commonly called fructose-isomerases due to their ability to interconvert glucose and fructose. The systematic name of this enzyme class is D-xylose aldose-ketose-isomerase. Other names in common use include D-xylose isomerase, D-xylose ketoisomerase, and D-xylose ketol-isomerase.

<span class="mw-page-title-main">Trehalulose</span> Chemical compound

Trehalulose is a disaccharide made up of a molecule of fructose bound to a molecule of glucose. Like isomaltulose, it is a structural isomer of sucrose that is present in small quantities in honey. It makes up 50% of sugars in the honeydew of silverleaf whiteflies and is synthesised from sucrose by some bacteria, such as Protaminombacter rubrum. Because the anomeric carbon of the fructose moiety is not involved in the glycosidic bond, it is a reducing sugar.

Reuteran, which is synthesized by reuteransucrase, is a complex α-glucan that is differentiated in part by the large amount of α(1-4) and α(1-6) linkages. The polysaccharide is made of repeating monosaccharide units of D-glucose. The glucose units are connected via alpha glyosidic bonds between the first carbon on one glucose to the fourth carbon on the next glucose molecule. Additional branching αlpha linkages occur between the sixth carbon of a glucose molecule and then the first carbon of the subsequent glucose molecule. These branches occur approximately every 5-7 glucose units.

Mutansucrase is a glucansucrase that transfers a D-glycosyl residue to a glucan chain from a sucrose molecule. The enzyme breaks down sucrose into D-fructose and D-glucose. Glucose is then added to a growing chain by mutansucrase in an ɑ-(1→3) glycosidic linkage making an insoluble glucan. The gene that encodes for Mutansucrase is called gtfJ in a manner similar to other glucosyltransferases.

References

  1. Ravaud, Stéphanie; Watzlawick, Hildegard; Haser, Richard; Mattes, Ralf; Aghajari, Nushin (2006-01-01). "Overexpression, purification, crystallization and preliminary diffraction studies of the Protaminobacter rubrum sucrose isomerase SmuA". Acta Crystallographica. Section F, Structural Biology and Crystallization Communications. 62 (Pt 1): 74–76. doi:10.1107/S1744309105041758. PMC   2150920 . PMID   16511267.