Details
| Original language | English |
|---|---|
| Pages (from-to) | 168-176 |
| Number of pages | 9 |
| Journal | PHYTOCHEMISTRY |
| Volume | 95 |
| Publication status | Published - 2 Aug 2013 |
Abstract
Glyoxylate is a peroxisomal intermediate of photorespiration, the recycling pathway for 2-phosphoglycolate (2-PG) produced by the oxygenase activity of Rubisco. Under hot and dry growth conditions, photorespiratory intermediates can accumulate and must be detoxified by alternative pathways, including plastidal reactions. Moreover, there is evidence that chloroplasts are capable of actively producing glyoxylate from glycolate. Further metabolic steps are unknown, but probably include a CO2 release step. Here, we report that CO 2 production from glycolate and glyoxylate in isolated tobacco chloroplasts can be inhibited by pyruvate, but not related compounds. We isolated a protein fraction that was enriched for the chloroplast pyruvate dehydrogenase complex (PDC). The fraction contained a protein complex of several MDa in size that included all predicted subunits of the chloroplast PDC and a so far unidentified HSP93-V/ClpC1 heat shock protein. Glyoxylate competitively inhibited NADH formation from pyruvate in this fraction. The Km for pyruvate and the Ki for glyoxylate were 330 and 270 μM, respectively. Glyoxylate decarboxylation was also enriched in this fraction and could be in turn inhibited by pyruvate. Based on these data, we suggest that the chloroplast PDC might be part of a pathway for glycolate and/or glyoxylate oxidation in chloroplasts.
Keywords
- Heat shock protein Hsp93-V, Photorespiration, Two-dimensional BN/SDS-PAGE
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
- Biochemistry, Genetics and Molecular Biology(all)
- Molecular Biology
- Agricultural and Biological Sciences(all)
- Plant Science
- Agricultural and Biological Sciences(all)
- Horticulture
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: PHYTOCHEMISTRY, Vol. 95, 02.08.2013, p. 168-176.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - A possible role for the chloroplast pyruvate dehydrogenase complex in plant glycolate and glyoxylate metabolism
AU - Blume, Christian
AU - Behrens, Christof
AU - Eubel, Holger
AU - Braun, Hans Peter
AU - Peterhänsel, Christoph
N1 - Funding information: This work was funded by the Deutsche Forschungsgemeinschaft as part of the research network PROMICS ( PE819/4-1 ). We thank Bernhard Huchzermeyer and Markus Niessen for helpful discussions.
PY - 2013/8/2
Y1 - 2013/8/2
N2 - Glyoxylate is a peroxisomal intermediate of photorespiration, the recycling pathway for 2-phosphoglycolate (2-PG) produced by the oxygenase activity of Rubisco. Under hot and dry growth conditions, photorespiratory intermediates can accumulate and must be detoxified by alternative pathways, including plastidal reactions. Moreover, there is evidence that chloroplasts are capable of actively producing glyoxylate from glycolate. Further metabolic steps are unknown, but probably include a CO2 release step. Here, we report that CO 2 production from glycolate and glyoxylate in isolated tobacco chloroplasts can be inhibited by pyruvate, but not related compounds. We isolated a protein fraction that was enriched for the chloroplast pyruvate dehydrogenase complex (PDC). The fraction contained a protein complex of several MDa in size that included all predicted subunits of the chloroplast PDC and a so far unidentified HSP93-V/ClpC1 heat shock protein. Glyoxylate competitively inhibited NADH formation from pyruvate in this fraction. The Km for pyruvate and the Ki for glyoxylate were 330 and 270 μM, respectively. Glyoxylate decarboxylation was also enriched in this fraction and could be in turn inhibited by pyruvate. Based on these data, we suggest that the chloroplast PDC might be part of a pathway for glycolate and/or glyoxylate oxidation in chloroplasts.
AB - Glyoxylate is a peroxisomal intermediate of photorespiration, the recycling pathway for 2-phosphoglycolate (2-PG) produced by the oxygenase activity of Rubisco. Under hot and dry growth conditions, photorespiratory intermediates can accumulate and must be detoxified by alternative pathways, including plastidal reactions. Moreover, there is evidence that chloroplasts are capable of actively producing glyoxylate from glycolate. Further metabolic steps are unknown, but probably include a CO2 release step. Here, we report that CO 2 production from glycolate and glyoxylate in isolated tobacco chloroplasts can be inhibited by pyruvate, but not related compounds. We isolated a protein fraction that was enriched for the chloroplast pyruvate dehydrogenase complex (PDC). The fraction contained a protein complex of several MDa in size that included all predicted subunits of the chloroplast PDC and a so far unidentified HSP93-V/ClpC1 heat shock protein. Glyoxylate competitively inhibited NADH formation from pyruvate in this fraction. The Km for pyruvate and the Ki for glyoxylate were 330 and 270 μM, respectively. Glyoxylate decarboxylation was also enriched in this fraction and could be in turn inhibited by pyruvate. Based on these data, we suggest that the chloroplast PDC might be part of a pathway for glycolate and/or glyoxylate oxidation in chloroplasts.
KW - Heat shock protein Hsp93-V
KW - Photorespiration
KW - Two-dimensional BN/SDS-PAGE
UR - http://www.scopus.com/inward/record.url?scp=84893804337&partnerID=8YFLogxK
U2 - 10.1016/j.phytochem.2013.07.009
DO - 10.1016/j.phytochem.2013.07.009
M3 - Article
C2 - 23916564
AN - SCOPUS:84893804337
VL - 95
SP - 168
EP - 176
JO - PHYTOCHEMISTRY
JF - PHYTOCHEMISTRY
SN - 0031-9422
ER -