Features of Using 2,6-Dichlorophenolindophenol as an Electron Acceptor in Photosynthesis Studiesстатья
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 8 апреля 2022 г.
Аннотация:2,6-dichlorophenolindophenol (DCPIP) is a redox indicator widely used to study electron transferreactions in biological systems, including in the process of photosynthesis. DCPIP exists in solution in twoforms, “pink” and “blue,” which transform into each other during protonation/deprotonation. Upon reduction,the DCPIP is discolored. We investigated the pH-dependence of DCPIP reduction rate in the presenceof the photosystem II (PSII) at two wavelengths: 522 nm (isobestic DCPIP point) and 600 nm (near theabsorption maximum of the deprotonated “blue” form). It was shown that, in experiments with a change ofthe pH medium, measuring at a wavelength of 600 nm requires corrections related to changes in the ratio ofthe “blue” and “pink” forms of the acceptor as well as using the pK parameter of this acceptor, whose рKvalues vary in various sources, to calculate the DCPIP reduction rate. Measurements at the isobestic point(522 nm) allowed for avoiding these complexities. We also found that the maximum at the pH-dependenceof the DCPIP reduction rate by PSII shifted by approximately 1 unit to the acidic region relative to the maximumof the acceptor pair 2,6-dichloro-p-benzoquinone–potassium ferricyanide reduction rate pH-dependence.This shift may be due to the lower availability of the QB site on the acceptor side of PSII for the chargeddeprotonated DCPIP form compared to the uncharged protonated form.