Ascorbate Peroxidase of Moss Dicranum scoparium: Gene Identification and Enzyme Activity.

In the present work, the APX gene encoding ascorbate peroxidase in the moss Dicranum scoparium was for the first time cloned and sequenced, and a high homology of APX with ascorbate peroxidase genes of the mosses Grimmia pilifera and Physcomitrella patens was shown. The structure of the protein was characterized using bioinfomatics approach, and the activity of the enzyme under abiotic stresses was studied. An increase in the activity of ascorbate peroxidase was detected during desiccation of D.

Activity of Redox Enzymes in the Thallus of Anthoceros natalensis.

Anthocerotophyta (hornworts) belong to a group of ancient nonvascular plants and originate from a common ancestor with contemporary vascular plants. Hornworts represent a unique model for investigating mechanisms of formation of stress resistance in higher plants due to their high tolerance to the action of adverse environmental factors. In this work, we demonstrate that the thallus of Anthoceros natalensis exhibits high redox activity changing under stress.

[Activation of extracellular peroxidase of wheat roots under the action of xenobiotics].

We studied the influence of xenobiotics of various chemical natures, including N,N'-dicyclohexylcarbodiimide, diethylstilbestrol, and chlorpromazine, on the activity of peroxidase, a redox-enzyme that participates in defense reactions of plants. It was shown that the influence of the studied xenobiotics on severed roots of wheat seedlings caused an increase in the permeability ofplasmalemma for K+ and H+ and stimulated the activity of the extracellular peroxidase that forms the superoxide radical anion. It is assumed that the extracellular peroxidase can initiate the transformation of alien compounds on the cell surface, before their entrance into the cells.

Effect of exogenous phenols on superoxide production by extracellular peroxidase from wheat seedling roots.

Competitive and complimentary relationships of various peroxidase substrates were studied to elucidate the enzymatic mechanisms underlying production of reactive oxygen species in plant cell apoplast. Dianisidine peroxidase released from wheat seedling roots was inhibited by ferulate and coniferol, while ferulic and coniferyl peroxidases were activated by o-dianisidine. Both ferulate and coniferol, when added together with hydrogen peroxide, stimulated superoxide production by extracellular peroxidase.