Biomaterial Database

The lysine-ketoglutarate reductase-saccharopine dehydrogenase is involved in the osmo-induced synthesis of pipecolic acid in rapeseed leaf tissues. 2006

M Moulin, and C Deleu, and F Larher, and A Bouchereau

Plant Metabolism, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.

Higher plant responses to abiotic stresses are associated with physiological and biochemical changes triggering a number of metabolic adjustments. We focused on L-lysine catabolism, and have previously demonstrated that degradation of this amino acid is osmo-regulated at the level of lysine-ketoglutarate reductase (LKR, EC 1.5.1.8) and saccharopine dehydrogenase (SDH, EC 1.5.1.9) in Brassica napus. LKR and SDH activities are enhanced by decreasing osmotic potential and decrease when the upshock osmotic treatment is followed by a downshock osmotic one. Moreover we have shown that the B. napus LKR/SDH gene is up-regulated in osmotically-stressed tissues. The LKR/SDH activity produces alpha-aminoadipate semialdehyde which could be further converted into alpha-aminoadipate and acetyl CoA. Alternatively alpha-aminoadipate could behave as a precursor for pipecolic acid. Pipecolic acid is described as an osmoprotectant in bacteria and is co-accumulated with proline in halophytic plants. We suggest that osmo-induction of the LKR/SDH activity could be partly responsible for pipecolic acid accumulation. This proposal has been assessed in this study through pipecolic acid amounts determination in rape leaf discs subjected to various upshift and downshift osmotic treatments. Changes in pipecolic acid level actually behave as those observed for LKR and SDH activities, since it increases or decreases in rape leaf discs treated under hyper- or hypo-osmotic conditions, respectively. In addition we show that pipecolic acid level is positively correlated with the external osmotic potential as well as with the duration of the applied treatment. On the other hand pipecolic acid level is related to the availability of L-lysine and not to that of D-lysine. Collectively the results obtained demonstrate that lysine catabolism through LKR/SDH activity is involved in osmo-induced synthesis of pipecolic acid.

UI	MeSH Term	Description	Entries
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D009997	Osmotic Pressure	The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.	Osmotic Shock,Hypertonic Shock,Hypertonic Stress,Hypotonic Shock,Hypotonic Stress,Osmotic Stress,Hypertonic Shocks,Hypertonic Stresses,Hypotonic Shocks,Hypotonic Stresses,Osmotic Pressures,Osmotic Shocks,Osmotic Stresses,Pressure, Osmotic,Pressures, Osmotic,Shock, Hypertonic,Shock, Hypotonic,Shock, Osmotic,Shocks, Hypertonic,Shocks, Hypotonic,Shocks, Osmotic,Stress, Hypertonic,Stress, Hypotonic,Stress, Osmotic,Stresses, Hypertonic,Stresses, Hypotonic,Stresses, Osmotic
D010875	Pipecolic Acids		Acids, Pipecolic
D010940	Plant Proteins	Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available.	Plant Protein,Protein, Plant,Proteins, Plant
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D000105	Acetyl Coenzyme A	Acetyl CoA participates in the biosynthesis of fatty acids and sterols, in the oxidation of fatty acids and in the metabolism of many amino acids. It also acts as a biological acetylating agent.	Acetyl CoA,Acetyl-CoA,CoA, Acetyl,Coenzyme A, Acetyl
D012443	Saccharopine Dehydrogenases	Amine oxidoreductases that use either NAD+ (EC 1.5.1.7) or NADP+ (EC 1.5.1.8) as an acceptor to form L-LYSINE or NAD+ (EC 1.5.1.9) or NADP+ (EC 1.5.1.10) as an acceptor to form L-GLUTAMATE. Deficiency of this enzyme causes HYPERLYSINEMIAS.	Saccharopine Dehydrogenase,Lysine-2-Oxoglutarate Reductase,Lysine-Ketoglutarate Reductase,Saccharopine Dehydrogenase (NAD+, L-Glutamate Forming),Saccharopine Dehydrogenase (NAD+, L-Lysine Forming),Saccharopine Dehydrogenase (NADP+, L-Glutamate Forming),Saccharopine Dehydrogenase (NADP+, L-Lysine Forming),Dehydrogenase, Saccharopine,Dehydrogenases, Saccharopine,Lysine 2 Oxoglutarate Reductase,Lysine Ketoglutarate Reductase,Reductase, Lysine-2-Oxoglutarate,Reductase, Lysine-Ketoglutarate
D018506	Gene Expression Regulation, Plant	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.	Plant Gene Expression Regulation,Regulation of Gene Expression, Plant,Regulation, Gene Expression, Plant
D018515	Plant Leaves	Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)	Plant Leaf,Leaf, Plant,Leave, Plant,Leaves, Plant,Plant Leave
D029741	Brassica rapa	A subspecies of Brassica that includes rape mustard. It is cultivated for the seed and used as animal feed.	Field Mustard,Wild Rutabaga,Wild Turnip,Field Mustards,Mustard, Field,Mustards, Field,Rutabaga, Wild,Rutabagas, Wild,Turnip, Wild,Turnips, Wild,Wild Rutabagas,Wild Turnips