Unusual pH-dependence of DIADINOXANTHIN (cas 18457-54-0) de-epoxidase activation causes chlororespiratory induced accumulation of diatoxanthin in the diatom Phaeodactylum tricornutum

Add time:09/05/2019    Source:sciencedirect.com

SummaryBased on our recent findings that in the diatom Phaeodactylum tricornutum, chlororespiration in periods of prolonged darkness leads to the accumulation of diatoxanthin (DT), we have elaborated in detail the interdependence between the chlororespiratory proton gradient and the activation of DIADINOXANTHIN (cas 18457-54-0) de-epoxidase (DDE). The data clearly demonstrates that activation of DDE in Phaeodactylum occurs at higher pH-values compared to activation of violaxanthin de-epoxidase (VDE) in higher plants. In thylakoid membranes as well as in enzyme assays with isolated DDE, the de-epoxidation of diadinoxanthin (DD) is efficiently catalyzed at pH 7.2. In comparison, de-epoxidation of violaxanthin (Vx) in spinach thylakoids is observed below pH 6.5. Phaeodactylum thylakoids isolated from high light grown cells, that also contain the pigments of the violaxanthin cycle, show violaxanthin de-epoxidation at higher pH-values, thus suggesting that in Phaeodactylum, one de-epoxidase converts both diadinoxanthin and violaxanthin. We conclude that the activation of DDE at higher pH-values can explain how the low rates of chlororespiratory electron flow, that lead to the build-up of a rather small proton gradient, can induce the observed accumulation of diatoxanthin in the dark. Furthermore, we show that dark activation of diadinoxanthin de-epoxidation is not restricted to Phaeodactylum tricornutum but was also found in another diatom, Cyclotella meneghiana

We also recommend Trading Suppliers and Manufacturers of DIADINOXANTHIN (cas 18457-54-0). Pls Click Website Link as below: cas 18457-54-0 suppliers

Prev:Research articleThe DIADINOXANTHIN (cas 18457-54-0) diatoxanthin cycle induces structural rearrangements of the isolated FCP antenna complexes of the pennate diatom Phaeodactylum tricornutum
Next:Regular paperThe lifetimes and energies of the first excited singlet states of DIADINOXANTHIN (cas 18457-54-0) and diatoxanthin: the role of these molecules in excess energy dissipation in algae)