Glyoxysome: Difference between revisions
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'''Glyoxysomes''' are specialized [[peroxisomes]] found in [[plants]] (particularly in the [[fat]] storage tissues of [[germination|germinating]] seeds) and also in filamentous fungi. Seeds that contain fats and oils include corn, soybean, sunflower, peanut and pumpkin.<ref name=":0">{{Cite journal|last=Graham|first=Ian A.|date=2008-01-01|title=Seed Storage Oil Mobilization|journal=Annual Review of Plant Biology|volume=59|issue=1|pages=115–142|doi=10.1146/annurev.arplant.59.032607.092938|pmid=18444898}}</ref> As in all peroxisomes, in glyoxysomes the fatty acids are oxidized to [[acetyl-CoA]] by peroxisomal β-oxidation enzymes. When the fatty acids are oxidized hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is produced as oxygen (O<sub>2</sub>) is consumed.<ref name=":0" /> Thus the seeds need oxygen to germinate. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of [[glyoxylate cycle]] ([[isocitrate lyase]] and [[malate synthase]]) which accomplish the [[glyoxylate cycle]] bypass. |
'''Glyoxysomes''' are specialized [[peroxisomes]] found in [[plants]] (particularly in the [[fat]] storage tissues of [[germination|germinating]] seeds) and also in filamentous fungi. Seeds that contain fats and oils include corn, soybean, sunflower, peanut and pumpkin.<ref name=":0">{{Cite journal|last=Graham|first=Ian A.|date=2008-01-01|title=Seed Storage Oil Mobilization|journal=Annual Review of Plant Biology|volume=59|issue=1|pages=115–142|doi=10.1146/annurev.arplant.59.032607.092938|pmid=18444898}}</ref> As in all peroxisomes, in glyoxysomes the fatty acids are oxidized to [[acetyl-CoA]] by peroxisomal β-oxidation enzymes. When the fatty acids are oxidized hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is produced as oxygen (O<sub>2</sub>) is consumed.<ref name=":0" /> Thus the seeds need oxygen to germinate. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of [[glyoxylate cycle]] ([[isocitrate lyase]] and [[malate synthase]]) which accomplish the [[glyoxylate cycle]] bypass. |
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Thus, glyoxysomes (as all peroxisomes) contain [[enzymes]] that initiate the breakdown of [[fatty acid]]s and additionally possess the enzymes to produce intermediate products for the synthesis of [[sugars]] by [[gluconeogenesis]]. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by [[photosynthesis]]. |
Thus, glyoxysomes (as all peroxisomes) contain [[enzymes]] that initiate the breakdown of [[fatty acid]]s and additionally possess the enzymes to produce intermediate products for the synthesis of [[sugars]] by [[gluconeogenesis]]. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by [[photosynthesis]]. |
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Revision as of 14:20, 24 April 2019
Glyoxysomes are specialized peroxisomes found in plants (particularly in the fat storage tissues of germinating seeds) and also in filamentous fungi. Seeds that contain fats and oils include corn, soybean, sunflower, peanut and pumpkin.[1] As in all peroxisomes, in glyoxysomes the fatty acids are oxidized to acetyl-CoA by peroxisomal β-oxidation enzymes. When the fatty acids are oxidized hydrogen peroxide (H2O2) is produced as oxygen (O2) is consumed.[1] Thus the seeds need oxygen to germinate. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of glyoxylate cycle (isocitrate lyase and malate synthase) which accomplish the glyoxylate cycle bypass.
Thus, glyoxysomes (as all peroxisomes) contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by photosynthesis.
Plant peroxisomes also participate in photorespiration and nitrogen metabolism in root nodules.
References
- Sengbusch, Peter V. (2003) Botany online: Peroxysomes and Glyoxysomes
- UniProt Knowledgebase keyword: Glyoxysome