Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
 4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphatidic acid (PA) is emerging as an important lipid signalling molecule. In plants, it is implicated in various stress-signalling pathways and is formed in response to wounding, osmotic stress, cold stress, pathogen elicitors, Nod factors, ethylene and abscisic acid. How PA exerts its effects is still unknown, mainly because of the lack of characterized PA targets. In an approach to isolate such targets we have used PA-affinity chromatography. Several PA-binding proteins were present in the soluble fraction of tomato and Arabidopsis cells. Using mass spectrometric analysis, several of these proteins, including Hsp90, 14-3-3 proteins, an SnRK2 serine/threonine protein kinase and the PP2A regulatory subunit RCN1 could be identified. As an example, the binding of one major PA-binding protein, phosphoenolpyruvate carboxylase (PEPC), was characterized further. Competition experiments with different phospholipids confirmed specificity for PA. Hypo-osmotic treatment of the cells increased the amount of PEPC that bound the PA beads without increasing the absolute amount of PEPC. This suggests that PEPC's affinity for PA had increased. The work shows that PA-affinity chromatography/mass spectrometry is an effective way to isolate and identify PA-binding proteins from plants.
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PMID:Isolation and identification of phosphatidic acid targets from plants. 1527 72

In addition to lactate and pyruvate, some amino acids were found to serve as potential gluconeogenic substrates in the perfused liver of Clarias batrachus. Glutamate was found to be the most effective substrate, followed by lactate, pyruvate, serine, ornithine, proline, glutamine, glycine, and aspartate. Four gluconeogenic enzymes, namely phosphoenolpyruvate carboxykinase (PEPCK), pyruvate carboxylase (PC), fructose 1,6-bisphosphatase (FBPase) and glucose 6-phosphatase (G6Pase) could be detected mainly in liver and kidney, suggesting that the latter are the two major organs responsible for gluconeogenic activity in this fish. Hypo-osmotically induced cell swelling caused a significant decrease of gluconeogenic efflux accompanied with significant decrease of activities of PEPCK, FBPase and G6Pase enzymes in the perfused liver. Opposing effects were seen in response to hyperosmotically induced cell shrinkage. These changes were partly blocked in the presence of cycloheximide, suggesting that the aniso-osmotic regulations of gluconeogenesis possibly occurs through an inverse regulation of enzyme proteins and/or a regulatory protein synthesis in this catfish. In conclusion, gluconeogenesis appears to play a vital role in C. batrachus in maintaining glucose homeostasis, which is influenced by cell volume changes possibly for proper energy supply under osmotic stress.
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PMID:Cell volume changes affect gluconeogenesis in the perfused liver of the catfish Clarias batrachus. 1538 55

The present study assesses the effects of osmotic stress on phosphoenolpyruvate carboxykinase (PEPCK), fructose 1,6-bisphosphatase (FBPase) and glucose 6-phosphatase (G6Pase) activities and (14)C-total lipid synthesis from (14)C-glycine in the anterior and posterior gills, jaw muscle, and hepatopancreas of Neohelice granulata. In posterior gills, 24-h exposure to hyperosmotic stress increased PEPCK, FBPase and G6Pase activities. Increase in (14)C-lipid synthesis was associated to the decrease in PEPCK activity after 72-h exposure to hyperosmotic stress. Hypo-osmotic stress decreased PEPCK and G6Pase activities in posterior gills; however, (14)C-lipids increased after 72-h exposure to stress. In anterior gills, decreases in the G6Pase activity after 72-h of hyperosmotic stress and in (14)C-lipogenesis after 144-h were observed, while PEPCK activity increased after 144 h. Exposure to hypo-osmotic stress increased (14)C-lipid synthesis and PEPCK activity in anterior gills. Muscle G6Pase activity increased after 72-h exposure to hypo-osmotic stress; however, no significant change was observed in the lipogenesis. PEPCK decreased in muscle after 144-h exposure to hyperosmotic, coinciding with increased (14)C-lipid synthesis. In the hepatopancreas, a decrease in the (14)C-lipogenesis occurred after 24-h exposure to hyperosmotic stress, accompanied by increase in (14)C-lipid synthesis. Additionally, PEPCK activity returned to control levels. The hepatopancreatic lipogenesis from amino acids was not involved in the metabolic adjustment during hypo-osmotic stress. However, gluconeogenesis is one of the pathways involved in the adjustment of the intracellular concentration of nitrogenated compounds.
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PMID:Effects of hypo- or hyperosmotic stress on lipid synthesis and gluconeogenic activity in tissues of the crab Neohelice granulata. 2113 Aug 93