| title: | Generation of active oxygen species by apoplastic peroxidases. A quantitative approach |
|---|---|
| reg no: | ETF5488 |
| project type: | Estonian Science Foundation research grant |
| subject: |
1.6-1.9. Chemistry and Molecular Biology 1.10-1.16. Bio-Geo Sciences |
| status: | completed |
| institution: | TU Faculty of Biology and Geography |
| head of project: | Heino Moldau |
| duration: | 01.01.2003 - 31.12.2004 |
| description: | The goal of the project is prediction of still unidentified reductants capable of producing active oxygen species (AOS) by plant cell apoplastic peroxidases in response to pathogenic invaders including anthropogenic ozone. A mathematical model of generation and removal of AOS by the indole-3-acetic acid/horseradish peroxidase/oxygen system (IAA/HRP/O2) in an early oxidative burst will be elaborated on the level of elementary (bio)chemical reactions, with special emphasis to the pH-dependence of AOS formation. The model will be formulated for a single plant cell and encounters transport of the reductant and hydrogen peroxide across plasmalemma. Based on the fact that each of the five oxidation forms of the unspecific heme peroxidases interact with different substrates in a qualitatively similar manner, the IAA/HRP/O2 system will be used as a model system to reach the goal. Employing the methods of computer chemistry and kinetic modelling, the intrinsic parameters of the model system ( pK values of enzyme and reductant and their mutual bimolecular rate constants, membrane permeabilities) will be varied and the calculated levels and pH dependencies of AOS production will be compared against measured rates of AOS formation by various substrate/peroxidase couples. A more general aim of the effort is to contribute to the evaluation of the molecular and biochemical mechanisms that determine and orchestrate transcriptionally induced multiple defence responses of plants to various pathogenic stressors. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Irina Bichele | Univ.of Tartu | res. sci. | |
| 2. | Heino Moldau | TU Faculty of Biology and Geography | res. sci. | |
| 3. | Evi Padu | Univ of Tartu | docent | |