Photosynthetic Formation of Hydrogen

Besides these external processes, formation of ROS may also take place intrac-ellularly. Photooxidative stress, including UVB, stimulates various cellular processes leading to the production of superoxide radicals and hydrogen peroxide, as well as singlet-oxygen and hydroxyl radicals. The sources and production sites of ROS are mainly related to photosynthetic activities such as the pseudocyclic photophosphorylation and the Mehler reaction, which stimulate the accumulation of hydrogen peroxide (Asada 1994 Elstner 1990). 

Photosynthetic Production of H2 and H2O2 on Semiconducting Oxide Grains in Aqueous Solutions Hydrogen peroxide formation observed in Ti02 powder suspensions as in Ref. 243 for Ti02 fdms. 248... 

The formation of a hydrogen bond between the amide proton and one carbonyl oxygen of NQ was indicated in the Ec + —NQ /M" complex to stabilize the complex (see above). Electron-transfer reactions were believed to be regulated through such noncovalent interactions that play an important role in biological ET systems, where electron donors and acceptors are usually bound to proteins at a fixed distance (123-127). Eor example, in the bacterial photosynthetic reaction center (bRC) from Rhodobacter Rb) sphaeroides, an electron is transferred from... 

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