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Cellulase is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharides:
Acarbose (INN) is an anti-diabetic drug used to treat diabetes mellitus type 2 and, in some countries, prediabetes. It is a generic sold in Europe and China as Glucobay, in North America as Precose, and in Canada as Prandase. It is cheap and popular in China, but not in the U.S. One physician explains that use in the U.S. is limited because it is not potent enough to justify the side effects of diarrhea and flatulence. However, a large study concluded in 2013 that "acarbose is effective, safe and well tolerated in a large cohort of Asian patients with type 2 diabetes." A possible explanation for the differing opinions is an observation that acarbose is significantly more effective in patients eating a relatively high carbohydrate Eastern diet.
A debranching enzyme is a molecule that helps facilitate the breakdown of glycogen, which serves as a store of glucose in the body, through glucosyltransferase and glucosidase activity. Together with phosphorylases, debranching enzymes mobilize glucose reserves from glycogen deposits in the muscles and liver. This constitutes a major source of energy reserves in most organisms. Glycogen breakdown is highly regulated in the body, especially in the liver, by various hormones including insulin and glucagon, to maintain a homeostatic balance of blood-glucose levels. When glycogen breakdown is compromised by mutations in the glycogen debranching enzyme, metabolic diseases such as Glycogen storage disease type III can result.
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.
β-Glucosidase is an enzyme that catalyses the following reaction:
The term glycosynthase refers to a class of proteins that have been engineered to catalyze the formation of a glycosidic bond. Glycosynthase are derived from glycosidase enzymes, which catalyze the hydrolysis of glycosidic bonds. They were traditionally formed from retaining glycosidase by mutating the active site nucleophilic amino acid to a small non-nucleophilic amino acid. More modern approaches use directed evolution to screen for amino acid substitutions that enhance glycosynthase activity.
Glycoside hydrolases catalyze the hydrolysis of glycosidic bonds in complex sugars. They are extremely common enzymes with roles in nature including degradation of biomass such as cellulose (cellulase), hemicellulose, and starch (amylase), in anti-bacterial defense strategies, in pathogenesis mechanisms and in normal cellular function. Together with glycosyltransferases, glycosidases form the major catalytic machinery for the synthesis and breakage of glycosidic bonds.
Oligo-1,6-glucosidase is a glucosidase enzyme located on the brush border of the small intestine, which catalyses the following reaction:
In enzymology, a xyloglucan-specific endo-beta-1,4-glucanase (EC 3.2.1.151) is an enzyme that catalyzes the chemical reaction
In enzymology, a peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase (EC 3.5.1.52) is an enzyme that catalyzes a chemical reaction that cleaves a N4-(acetyl-beta-D-glucosaminyl)asparagine residue in which the glucosamine residue may be further glycosylated, to yield a (substituted) N-acetyl-beta-D-glucosaminylamine and a peptide containing an aspartate residue. This enzyme belongs to the family of hydrolases, specifically those acting on carbon-nitrogen bonds other than peptide bonds in linear amides.
Neutral alpha-glucosidase AB is an enzyme that in humans is encoded by the GANAB gene.
GBA2 is the gene that encodes the enzyme non-lysosomal glucosylceramidase in humans. It has glucosylceramidase activity.
A ureohydrolase is a type of hydrolase enzyme. The ureohydrolase superfamily includes arginase, agmatinase, formiminoglutamase and proclavaminate amidinohydrolase. These enzymes share a 3-layer alpha-beta-alpha structure, and play important roles in arginine/agmatine metabolism, the urea cycle, histidine degradation, and other pathways.
Inulinase is an enzyme with systematic name 1-β-D-fructan fructanohydrolase. It catalyses the reaction
Xylan 1,4-β-xylosidase is an enzyme with systematic name 4-β-D-xylan xylohydrolase. This enzyme catalyses the following chemical reaction
Xylan 1,3-β-xylosidase is an enzyme with systematic name 3-β-D-xylan xylohydrolase. It catalyses the hydrolysis of successive xylose residues from the non-reducing termini of (1→3)-β-D-xylans.
Glucan 1,4-alpha-maltohydrolase is an enzyme with systematic name 4-alpha-D-glucan alpha-maltohydrolase. This enzyme catalyses the following chemical reaction
Neopullulanase is an enzyme of the alpha-amylase family with systematic name pullulan 4-D-glucanohydrolase (panose-forming). This enzyme principally catalyses the following chemical reaction by cleaving pullulan's alpha-1,4-glucosidic bonds:
Oligoxyloglucan reducing-end-specific cellobiohydrolase is an enzyme with systematic name oligoxyloglucan reducing-end cellobiohydrolase. This enzyme catalyses the following chemical reaction
Oligosaccharide reducing-end xylanase is an enzyme with systematic name beta-D-xylopyranosyl-(1->4)-beta-D-xylopyranose reducing-end xylanase. This enzyme catalyses the following chemical reaction
References
- ↑ Moracci M, Cobucci Ponzano B, Trincone A, Fusco S, De Rosa M, van Der Oost J, Sensen CW, Charlebois RL, Rossi M (July 2000). "Identification and molecular characterization of the first alpha -xylosidase from an archaeon". The Journal of Biological Chemistry. 275 (29): 22082–9. doi: 10.1074/jbc.M910392199 . PMID 10801892.
- ↑ Sampedro J, Sieiro C, Revilla G, González-Villa T, Zarra I (June 2001). "Cloning and expression pattern of a gene encoding an alpha-xylosidase active against xyloglucan oligosaccharides from Arabidopsis". Plant Physiology. 126 (2): 910–20. doi:10.1104/pp.126.2.910. PMC 111180 . PMID 11402218.
- ↑ Crombie HJ, Chengappa S, Jarman C, Sidebottom C, Reid JS (January 2002). "Molecular characterisation of a xyloglucan oligosaccharide-acting alpha-D-xylosidase from nasturtium (Tropaeolum majus L.) cotyledons that resembles plant 'apoplastic' alpha-D-glucosidases". Planta. 214 (3): 406–13. doi:10.1007/s004250100631. PMID 11859845.
- ↑ Lovering AL, Lee SS, Kim YW, Withers SG, Strynadka NC (January 2005). "Mechanistic and structural analysis of a family 31 alpha-glycosidase and its glycosyl-enzyme intermediate". The Journal of Biological Chemistry. 280 (3): 2105–15. doi: 10.1074/jbc.m410468200 . PMID 15501829.
- ↑ Iglesias N, Abelenda JA, Rodiño M, Sampedro J, Revilla G, Zarra I (January 2006). "Apoplastic glycosidases active against xyloglucan oligosaccharides of Arabidopsis thaliana". Plant & Cell Physiology. 47 (1): 55–63. doi: 10.1093/pcp/pci223 . PMID 16267099.
- ↑ Okuyama M, Kaneko A, Mori H, Chiba S, Kimura A (May 2006). "Structural elements to convert Escherichia coli alpha-xylosidase (YicI) into alpha-glucosidase". FEBS Letters. 580 (11): 2707–11. doi:10.1016/j.febslet.2006.04.025. PMID 16631751.
- ↑ Larsbrink J, Izumi A, Ibatullin FM, Nakhai A, Gilbert HJ, Davies GJ, Brumer H (June 2011). "Structural and enzymatic characterization of a glycoside hydrolase family 31 α-xylosidase from Cellvibrio japonicus involved in xyloglucan saccharification" (PDF). The Biochemical Journal. 436 (3): 567–80. doi:10.1042/bj20110299. PMID 21426303.
