Proline accumulates in many plant species in response to environmental stresses. Upon relief from stress, proline is rapidly oxidized in mitochondria by proline dehydrogenase (ProDH) and then by pyrroline-5-carboxylate dehydrogenase (P5CDH). Two ProDH genes have been identified in the genome of the model plant Arabidopsis thaliana . To gain a better understanding of ProDH1 functions in mitochondria, proteomic analysis was performed. ProDH1 polypeptides were identified in Arabidopsis mitochondria by immunoblotting gels after 2D blue native - SDS/PAGE, probing them with an anti-ProDH antibody and analysing protein spots by MS. The 2D gels showed that ProDH1 forms part of a low-molecular-weight (70-140 kDa) complex in the mitochondrial membrane. To evaluate the contribution of each isoform to proline oxidation, mitochondria were isolated from wild type and prodh1 , prodh2, prodh1prodh2 and p5cdh mutants. ProDH activity was high for genotypes in which ProDH, most likely ProDH1, was strongly induced by proline. Respiratory measurements indicate that ProDH1 has a role in oxidising excess proline and transferring electrons to the respiratory chain.
- Arabidopsis thaliana
- Electron transfer chain
- Proline dehydrogenase
- ©2016 The Author(s)
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