DCMU 5477402 226118854 2008-07-16T22:10:11Z Thijs!bot 1392310 robot Adding: [[cs:Diuron]] {{Chembox new | ImageFile = Diuron.png | OtherNames = 3-(3,4-dichlorophenyl)-1,1-dimethylurea | Section1 = {{Chembox Identifiers | CASNo = 330-54-1 }} | Section2 = {{Chembox Properties | Formula = C<sub>9</sub>H<sub>10</sub>Cl<sub>2</sub>N<sub>2</sub>O | MolarMass = 233.10 g/mol | Density = 1.48 g/cm<sup>3</sup> | MeltingPt = 158 &deg;C | BoilingPt = 180 &deg;C | Solubility = 42 mg/L }} | Section7 = {{Chembox Hazards | EUClass = Harmful ('''Xn'''); Dangerous for the environment ('''N''') }} }} '''DCMU''' ('''3-(3,4-dichlorophenyl)-1,1-dimethylurea''') is a [[herbicide]] that inhibits [[photosynthesis]]. It was released by [[Bayer]] in 1954 under the name of Diuron. ==Mechanism of action== DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the [[plastoquinone]] binding site of [[photosystem]] II, disallowing the electron flow from where it is generated, in photosystem II, to plastoquinone<ref>1</ref>. This interrupts the photosynthetic [[electron transport chain]] in photosynthesis and thus blocks the ability of the plant to turn light energy into chemical energy ([[adenosine triphosphate|ATP]] and [[reductant|reductant potential]]). DCMU only blocks electron flow from photosystem II, it has no effect on photosystem I or other reactions in photosynthesis, such as light absorption or carbon fixation in the [[Calvin cycle]]. However, because it absorbs electrons [[oxidized]] from water in [[PS II]], the electron "hole" of [[PS I]] cannot be satisfied, effectively shutting down photosynthesis by blocking the reduction of NADP<sup>+</sup> to NADPH, and the cyclic photosynthetic pathway since electron shuttling is associated with proton pumping across the membrane into the [[lumen]]. ==Applications== Besides its use a herbicide, DCMU is often used to research energy flow in [[photosynthesis]]. ==References== {{Unreferenced|date =September 2007}} <references/> <ref>1</ref>''FEBS Letters'' (1986) '''205''', 269-274 [[Category:Herbicides]] [[Category:Ureas]] [[Category:Toxicology]] [[cs:Diuron]] [[de:DCMU]] [[es:Diuron]] [[fr:Diuron]] [[nl:Diuron]] [[pl:Diuron]]