In enzymology, a pectin lyase also known as pectolyase is a naturally occurring pectinase

Pectinase

Pectinase is a general term for enzymes, such as pectolyase, pectozyme and polygalacturonase, commonly referred to in brewing as pectic enzymes. These break down pectin, a polysaccharide substrate that is found in the cell walls of plants. One of the most studied and widely used commercial...

 a type of enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that degrades pectin

Pectin

Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot...

. It is produced commercially for the food industry from fungi and used to destroy residual fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 starch

Starch

Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

, known as pectin

Pectin

Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot...

, in wine

Wine

Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...

 and cider

Cider

Cider or cyder is a fermented alcoholic beverage made from apple juice. Cider varies in alcohol content from 2% abv to 8.5% abv or more in traditional English ciders. In some regions, such as Germany and America, cider may be termed "apple wine"...

. In plant cell culture, it is used in combination with the enzyme cellulase

Cellulase

400px|thumb|right|alt = Colored dice with checkered background|Ribbon representation of the Streptomyces lividans beta-1,4-endoglucanase catalytic domain - an example from the family 12 glycoside hydrolases...

 to generate protoplast

Protoplast

Protoplast, from the ancient Greek πρῶτον + verb πλάθω or πλάττω , initially referred to the first organized body of a species.Protoplast has several biological definitions:...

s by degrading the plant cell walls.

Pectin lyase is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that catalyzes

Catalysis

Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 the chemical reaction

Chemical reaction

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

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 lyase

Lyase

In biochemistry, a lyase is an enzyme that catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure...

s, 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

Tertiary structure

In biochemistry and molecular biology, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates.-Relationship to primary structure:...

 have been solved for this class of enzymes, with PDB

Protein Data Bank

The Protein Data Bank is a repository for the 3-D structural data of large biological molecules, such as proteins and nucleic acids....

accession codes , , and .

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 juices clarification by pectin lyases.

The alkaline pectinase are inappropriate to be used in the food industries due to 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 need to be extensively investigated further.