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Pectinesterase (EC 3.1.1.11; systematic name pectin pectylhydrolase) is a ubiquitous cell-wall-associated enzyme that presents several isoforms that facilitate plant cell wall modification and subsequent breakdown. It catalyzes the following reaction:
Pectin is composed of complex polysaccharides that are present in the primary cell walls of a plant, and are abundant in the green parts of terrestrial plants. [5] Pectin is the principal component of the middle lamella, where it binds cells. Pectin is deposited by exocytosis into the cell wall via vesicles produced in the Golgi apparatus. [6]
Polygalacturonase is a pectinase, an enzyme that degrades pectin by hydrolyzing the O-glycosyl bonds in pectin's polygalacturonan network, resulting in α-1,4-polygalacturonic residues. [10] The rate of hydrolysis is dependent on polysaccharide chain length. Low rates of hydrolysis are associated with very short chains (e.g. digalacturonic acid ...
Modified citrus pectin (also known as depolymerized pectin, fractioned pectin, modified pectin, pH-modified pectin, low molecular weight pectin, and MCP) is a more digestible form of pectin. Modified citrus pectin is composed predominantly of D-polygalacturonates, which are more easily absorbed by the human digestive system. [2]
The pectin lyase is playing a crucial role in many biotechnological uses including the textile industry, paper manufacturing, wastewater pretreatment of pectin, clarifying of the juice, and extraction of oil. It has the ability to efficiently break the pectin molecule's back bone by β-eliminating in order to form pectin-oligosaccharide.
Nutrition polysaccharides are common sources of energy. Many organisms can easily break down starches into glucose; however, most organisms cannot metabolize cellulose or other polysaccharides like cellulose, chitin, and arabinoxylans. Some bacteria and protists can metabolize these carbohydrate types.
In acid-catalyzed Fischer esterification, the proton binds to oxygens and functions as a Lewis acid to activate the ester carbonyl (top row) as an electrophile, and converts the hydroxyl into the good leaving group water (bottom left). Both lower the kinetic barrier and speed up the attainment of chemical equilibrium.
The degree of polymerization increases steadily during the whole polymerization process. The type of polymerization of a given monomer usually depends on the functional groups present, and sometimes also on whether the monomer is linear or cyclic. Chain-growth polymers are usually addition polymers by Carothers' definition.