Sandbox Reserved 711: Difference between revisions
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== The catalysed reaction == | == The catalysed reaction == | ||
The endopolygalacturonase II is an endo-acting enzyme that hydrolyses alpha(1,4)-glycosidic bonds between the D-galacturonic acid monomeres of pectin chains. One of its particularities is the inversion of configuration that occurs during the reaction. Its functionning is optimal at a pH of 4.2 and with a non-methylated substrate. | The endopolygalacturonase II is an endo-acting enzyme that hydrolyses alpha(1,4)-glycosidic bonds between the D-galacturonic acid monomeres of pectin chains. One of its particularities is the inversion of configuration that occurs during the reaction. Its functionning is optimal at a pH of 4.2 and with a non-methylated substrate.<ref>http://onlinelibrary.wiley.com/doi/10.1046/j.1432-1327.1999.00080.x/full</ref> | ||
[[Image:mechanisme.png |center]] | [[Image:mechanisme.png |center]] | ||
The putative mechanism is the following: | The putative mechanism is the following: | ||
Asp180 and Asp202 bind the water molecule used in the hydrolyse and activate it, while Asp201, which is less exposed to the aqueous solvent, is stabilized its protonated state. In theses conditions, a bond can be built between the oxygen of the water and the carbon 1 of the galacturonic acid, whereas the bond between this carbon and the oxygen of the glycosidic bond is cleaved, the oxygen taking the proton released by Asp201. | Asp180 and Asp202 bind the water molecule used in the hydrolyse and activate it, while Asp201, which is less exposed to the aqueous solvent, is stabilized its protonated state. In theses conditions, a bond can be built between the oxygen of the water and the carbon 1 of the galacturonic acid, whereas the bond between this carbon and the oxygen of the glycosidic bond is cleaved, the oxygen taking the proton released by Asp201. | ||
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== References == | == References == | ||
<references/> | |||
== External links == | == External links == | ||