Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of mitochondria during seed germination is essential for plant growth. However, the developmental process is still poorly understood. Temperature plays a key role in soybean germination, and in this study we characterized the mitochondrial ultrastructure and proteome after imbibition at 22, 10 and 4 degrees C for 24 h. The mitochondria from the soybean seed axis can be divided into light and heavy mitochondria by Percoll density gradient centrifugation. The axes imbibed at 4 degrees C mainly contained light mitochondria, which had lower levels of specific mitochondrial enzymes and oxidative phosphorylation activity. In contrast, the axes imbibed at 22 degrees C mainly contained heavy mitochondria, which exhibited higher metabolism. Electron microscopy revealed that mitochondria in the axes imbibed at 4 degrees C had a poorly developed internal membrane system with few cristae, while the mitochondria in the axes imbibed at 22 degrees C developed more normally. Furthermore, we compared the axis mitochondrial proteomes during imbibition at different temperatures. The differentially expressed proteins were identified using ESI-Q-TOF-MS/MS (electrospray ionization quadrupole time-of-flight tandem mass spectrometry). Proteins involved in mitochondrial metabolites including malate dehydrogenase (tricarboxylic acid cycle enzyme), putative ATP synthase subunit (oxidative phosphorylation complex subunits), mitochondrial chaperonin-60 (heat shock protein), arginase (urea cycle enzyme) and mitochondrial elongation factor Tu (mitochondrial genome transcript enzyme) were identified. The reduced expression of these proteins might not support normal mitochondrial metabolism. We conclude that chilling during imbibition causes mitochondrial damage at both ultrastructural and metabolic levels.
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PMID:Mitochondrial damage in the soybean seed axis during imbibition at chilling temperatures. 1952 Jun 72

Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and fruit carbohydrates may be plenty, whereas oxygen levels are falling. Several enzymatic complexes in mitochondrial electron transport chain (ETC) are capable of reactive oxygen species (ROS) formation under physiological and pathological conditions. Inherently connected parameters such as the redox state of electron carriers in the ETC, ATP synthase activity and inner mitochondrial membrane potential, when affected by external stimuli, can give rise to ROS formation via complexes I and III, and by reverse electron transport (RET) from complex II. Superoxide radicals produced are quickly scavenged by superoxide dismutase (MnSOD), and the resulting H(2)O(2) is detoxified by peroxiredoxin-thioredoxin system or by the enzymes of ascorbate-glutathione cycle, found in the mitochondrial matrix. Arginine-dependent nitric oxide (NO)-releasing activity of enzymatic origin has been detected in plant mitochondria. The molecular identity of the enzyme is not clear but the involvement of mitochondria-localized enzymes responsible for arginine catabolism, arginase and ornithine aminotransferase has been shown in the regulation of NO efflux. Besides direct control by antioxidants, mitochondrial ROS production is tightly controlled by multiple redundant systems affecting inner membrane potential: NAD(P)H-dependent dehydrogenases, alternative oxidase (AOX), uncoupling proteins, ATP-sensitive K(+) channel and a number of matrix and intermembrane enzymes capable of direct electron donation to ETC. NO removal, on the other hand, takes place either by reactions with molecular oxygen or superoxide resulting in peroxynitrite, nitrite or nitrate ions or through interaction with non-symbiotic hemoglobins or glutathione. Mitochondrial ROS and NO production is tightly controlled by multiple redundant systems providing the regulatory mechanism for redox homeostasis and specific ROS/NO signaling.
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PMID:Reactive oxygen species and nitric oxide in plant mitochondria: origin and redundant regulatory systems. 2005 31