Xanthan lyase

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In enzymology, a xanthan lyase (EC 4.2.2.12) is an enzyme that catalyzes the chemical reaction of cleaving the beta-D-mannosyl-beta-D-1,4-glucuronosyl bond on the polysaccharide xanthan. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. Xanthan lyase was first identified and partially-purified in 1987.[1]

Xanthan is a polysaccharide secreted by several bacteria, such as the plant pathogen Xanthomonas campestris, and it consists of a main linear chain based on cellulose with side chains attached to alternate glucosyl (glucose) residues.[2] These side chains contain three monosaccharide residues. Xanthan lyase is produced by bacteria that degrade this polysaccharide, such as Bacillus, Corynebacterium and Paenibacillus species.[2][3]

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[edit] Industrial applications

Xanthan is used in industry as a thickening agent in foods and drinks, as a stabilizing agent for foams, as a means of enhancing oil recovery and in the manufacture of good such as paints, cosmetics and explosives.[3] The use of xanthan lyase as a means of altering the physical properties of xanthans is an area of current research in biotechnology.

[edit] Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1J0M, 1J0N, 1X1H, 1X1I, 1X1J, 2E22, and 2E24. The enzyme from Bacillus is a monomer consisting of two domains: an alpha helical N-terminal domain, and a C-terminal domain composed of beta sheets.[4] The active site is a deep cleft located between these two domains.

[edit] References

  1. ^ Sutherland IW (1987). "Xanthan lyases--novel enzymes found in various bacterial species". J. Gen. Microbiol. 133 (11): 3129–34. PMID 3446747. 
  2. ^ a b Hashimoto W, Miki H, Tsuchiya N, Nankai H, Murata K (1998). "Xanthan lyase of Bacillus sp. strain GL1 liberates pyruvylated mannose from xanthan side chains". Appl. Environ. Microbiol. 64 (10): 3765–8. PMID 9758797. 
  3. ^ a b Ruijssenaars HJ, de Bont JA, Hartmans S (1999). "A pyruvated mannose-specific xanthan lyase involved in xanthan degradation by Paenibacillus alginolyticus XL-1". Appl. Environ. Microbiol. 65 (6): 2446–52. PMID 10347025. 
  4. ^ Hashimoto W, Nankai H, Mikami B, Murata K (2003). "Crystal structure of Bacillus sp. GL1 xanthan lyase, which acts on the side chains of xanthan". J. Biol. Chem. 278 (9): 7663–73. PMID 12475987. 

[edit] External links

The CAS registry number for this enzyme class is 113573-69-6.

[edit] Gene Ontology (GO) codes

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