Pectin lyase
| pectin lyase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 4.2.2.10 | ||||||||
| CAS no. | 9033-35-6 | ||||||||
| 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 | ||||||||
| |||||||||
In enzymology, a pectin lyase also known as pectolyase is a naturally occurring pectinase a type of enzyme that degrades pectin. It is produced commercially for the food industry from fungi and used to destroy residual fruit starch, known as pectin, in wine and cider. In plant cell culture, it is used in combination with the enzyme cellulase to generate protoplasts by degrading the plant cell walls.
Pectin lyase is an enzyme that catalyzes the chemical reaction
- Eliminative cleavage of (1->4)-alpha-D-galacturonan methyl ester to give oligosaccharides with 4-deoxy-6-O-methyl-alpha-D-galact-4-enuronosyl groups at their non-reducing ends
This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides.
Nomenclature
The systematic name of this enzyme class is (1->4)-6-O-methyl-alpha-D-galacturonan lyase. Other names in common use include:
- endo-pectin lyase,
- pectin methyltranseliminase,
- pectin trans-eliminase,
- pectolyase,
- PL,
- PMGL,
- PNL, and
- polymethylgalacturonic transeliminase.
Structural studies
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1IDJ, 1IDK, and 1QCX.
Biotechnology applications
Pectin lyases are the only known pectinases capable of degrading highly esterified pectins (like those found in fruits) into small molecules via β-elimination mechanism without producing methanol (which is toxic), in contrast with the combination of PG and PE, which are normally found in commercial products. In addition, the presence of undesirable enzymatic activity in commercial pectinases may be detrimental to aroma because they are responsible for producing unpleasant volatile off flavour. There are many reports of fruit juice clarification by pectin lyases.
The alkaline pectinase is inappropriate for use in the food industry due to the acidic pH of fruit juices. However, they have a very high demand in the textile industries. They are used for retting of plant fibers such as ramie, sunn hemp, jute, flax and hemp. The first report on retting of sunn hemp (Crotalaria juncea) by pectin lyase produced by Aspergillus flavus MTCC 7589 was published in 2008 but this aspect of pectin lyases needs to be extensively investigated further.[1][2][3][4]
References
- ^ Yadav S, Yadav PK, Yadav D, Yadav KD (2008). "Purification and characterisation of an acidic pectin lyase produced byAspergillus ficuum strain MTCC 7591 suitable for clarification of fruit juices". Annals of Microbiology. 58 (1): 61–65. doi:10.1007/BF03179446.
- ^ Yadav S, Yadav PK, Yadav D, Yadav KD (2008). "Purification and characterization of an alkaline pectin lyase from Aspergillus flavus". Process Biochem. 43 (5): 547–552. doi:10.1016/j.procbio.2008.01.015.
- ^ Mantovani CF, Geimba MP, Brandelli A (2005). "Enzymatic clarification of fruit juices by fungal pectin lyase". Food Biotechnol. 19 (3): 173–181. doi:10.1080/08905430500316284.
- ^ Kapoor M, Beg QK, Bhushan B, Singh K, Dadhich KS, Hoondal GS (2001). "Application of alkaline thermostable polygalacturonase from Bacillus sp. MG-ep-2 in degumming of ramie (Boehemeria nivea) and sunn hemp (Crotalaria juncea) bast fibers". Process Biochem. 6: 803–807.
Further reading
- Albersheim P, Neukom H, Deuel H (1960). "Uber die Bildung von ungesattigten Abbauprodukten durch ein pekinabbauendes Enzym". Helv. Chim. Acta. 43 (5): 1422–1426. doi:10.1002/hlca.19600430525.
- Pickersgill R, Jenkins J (1997). "Two crystal structures of pectin lyase A from Aspergillus reveal a pH driven conformational change and striking divergence in the substrate-binding clefts of pectin and pectate lyases". Structure. 5 (5): 677–89. doi:10.1016/S0969-2126(97)00222-0. PMID 9195887.
- Kester HC, Visser J (1994). "Purification and characterization of pectin lyase B, a novel pectinolytic enzyme from Aspergillus niger". FEMS Microbiol. Lett. 120 (1–2): 63–68. doi:10.1111/j.1574-6968.1994.tb07008.x.
- Mutenda KE, Korner R, Christensen TM, Mikkelsen J, Roepstorff P (2002). "Application of mass spectrometry to determine the activity and specificity of pectin lyase A". Carbohydr. Res. 337 (13): 1217–27. doi:10.1016/S0008-6215(02)00127-1. PMID 12110197.