Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
 6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1) Liver cells from starved rats were incubated with 10 mM L-lactate, 1 mM pyruvate and 0.3 microM glucagon in the presence and absence of the mild respiratory inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) at 0.5 mM. (2) The whole cell concentrations of phosphoenolpyruvate, 2-phosphoglycerate and 3-phosphoglycerate increased about 2-fold, whilst the triose and hexose phosphate concentrations all decreased significantly. Similar results were obtained with 0.15 microM oligomycin and 10 microM atractyloside. (3) These data can be explained by a substantial decrease in the cytosolic free concentration ratio of ATP/ADP acting on the equilibrium of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase. (4) The increase in cytosolic phosphoenolpyruvate concentration can account for the observed increase in pyruvate kinase flux that occurs under these conditions (Pryor et al. (1987) Biochem. J. 247, 449-457). (5) An inhibition of pyruvate carboxylase was also implied by a decrease in calculated tissue oxaloacetate concentrations, confirming a role for both enzymes in the inhibition of gluconeogenesis. (6) Whole cell concentrations of effectors of pyruvate carboxylase activity were measured; only the ATP/ADP ratio decreased significantly. (7) Subcellular fractionation studies showed a good correlation between the measured mitochondrial ATP/ADP ratio and rates of gluconeogenesis both in the presence and absence of oleate. (8) A similar correlation could be observed between rates of pyruvate carboxylation and the measured matrix ATP/ADP ratio in isolated liver mitochondria from starved rats. (9) Data are also presented suggesting an additional effect of DCMU on the rate pyruvate carboxylation in situ under some circumstances, mediated by decreases in mitochondrial acetyl-CoA and cytosolic pyruvate concentrations. (10) It is noted that the effects of phenylethylbiguanide (phenformin) on the rate of gluconeogenesis and metabolite profiles in the perfused liver (Cooke et al. (1973) J. Biol. Chem. 248, 5272-5277) are similar to those caused by DCMU, supporting a mitochondrial locus of action for this hypoglycaemic agent.
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PMID:The mechanisms by which mild respiratory chain inhibitors inhibit hepatic gluconeogenesis. 845 80

The patterns of light activation of 4 chloroplastic enzymes were examined in mesophyll protoplasts of pea (Pisum sativum) in the absence or presence of oligomycin (inhibitor of oxidative phosphorylation) or antimycin A (inhibitor of cytochrome pathway) or salicylhydroxamic acid (SHAM, inhibitor of alternative pathway). The results were compared with those of DCMU (inhibitor of photosynthetic electron transport). The light activation of NADP glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH), fructose-1,6-bisphosphatase (FBPase), phosphoribulokinase (PRK) (enzymes of the Calvin cycle) and NADP malate dehydrogenase (NADP-MDH) (reflects chloroplast redox state) was more pronounced at limiting CO2 (0.1 mM NaHCO3) than that at optimal CO2 (1.0 mM NaHCO3). SHAM decreased markedly (up to 33%) the light activation of all 4 enzymes, while antimycin A or oligomycin exerted only a limited effect (<10% decrease). Antimycin A or oligomycin or SHAM had no significant effect on light activation of these 4 enzymes in isolated chloroplasts. However, DCMU caused a remarkable decrease in light activation of enzymes in both protoplasts (up to 78%) and chloroplasts (up to 69%). These results suggest that the restriction of alternative pathway of mitochondrial metabolism results in a marked decrease in the light activation of key chloroplastic enzymes in mesophyll protoplasts but not in isolated chloroplasts. Such a decrease in the light activation of enzymes could be also a secondary feedback effect because of the restriction on carbon assimilation.
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PMID:Consequence of restricted mitochondrial oxidative metabolism on photosynthetic carbon assimilation in mesophyll protoplasts: Decrease in light activation of four chloroplastic enzymes. 1147 20

Activities of Calvin-Benson cycle enzymes were found in protoplasts of guard cells from Vicia faba L. The activities of NADP-glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPD) and ribulose-1,5-bisphosphate carboxylase (RuBPC) were 2670 and 52 micromoles per milligrams chlorophyll per hour, respectively. Activities of NADP-GAPD and RuBPC in guard cells were increased by red light illumination, and the light activations were inhibited completely by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosystem II. Enzymes related to the Calvin-Benson cycle such as 3-phosphoglycerate kinase (PGAK), triose phosphate (TP) isomerase, and fructose-1,6-bisphosphatase (FBPase) were shown to be present in guard-cell chloroplasts. From these results, we conclude that the photosynthetic carbon reduction pathway is present in guard-cell chloroplasts of Vicia faba. We compared these enzyme activities in guard cells with those in mesophyll cells. The activities of NADP-GAPD and PGAK were more than several-fold higher and that of TP isomerase was much higher in guard-cell chloroplasts than in mesophyll chloroplasts. In contrast, activities of RuBPC and FBPase were estimated to be roughly half of those in mesophyll chloroplasts. High activities of PGAK, NAD-GAPD, and TP isomerase were found in fractions enriched in cytosol of guard cells. Illumination of guard-cell protoplasts with red light increased the cellular ATP/ADP ratio from 5 to 14. These results support the interpretation that guard cells utilize a shuttle system (e.g. phosphoglycerate [PGA]/dihydroxyacetone phosphate [DHAP] shuttle) for an indirect transfer of ATP and reducing equivalents from chloroplasts to the cytosol.
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PMID:Calvin-Benson Cycle Enzymes in Guard-Cell Protoplasts from Vicia faba L: Implications for the Greater Utilization of Phosphoglycerate/Dihydroxyacetone Phosphate Shuttle between Chloroplasts and the Cytosol. 1666 51

Effects of oxygen and photosynthesis and respiration inhibitors on the electron transport in photosystem I (PSI) of the cyanobacterium Arthrospira platensis cells were studied. Redox transients of P700 were induced by illumination at 730 nm and monitored as kinetics of the absorption changes at 810 nm; to block electron influx from PSII, the measurements were performed in the presence of 30 microM 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Inhibitors of terminal oxidases (potassium cyanide and pentachlorophenol) insignificantly influenced the fast oxidation of P700 under aerobic conditions, whereas removal of oxygen significantly decelerated the accumulation of P700(+). In the absence of oxygen the slow oxidation of P700 observed on the first illumination was accelerated on each subsequent illumination, suggesting an activation of the carbon cycle enzymes. Under the same conditions, pentachlorophenol (an uncoupler) markedly accelerated the P700 photooxidation. Under anaerobic conditions, potassium cyanide (an inhibitor of carbon dioxide assimilation) failed to influence the kinetics of redox transients of P700, whereas iodoacetamide (an inhibitor of NADP(H)-glyceraldehyde-3-phosphate dehydrogenase) completely prevented the photooxidation of P700. Thus, the fast photooxidation of P700 in the A. platensis cells under aerobic conditions in the presence of DCMU was caused by electron transport from PSI onto oxygen, and complicated transient changes in the P700 photooxidation kinetics under anaerobic conditions (in the presence of DCMU) were due to involvement of NADP+ generated during the reducing phase of the carbon cycle.
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PMID:Effects of oxygen and photosynthesis carbon cycle reactions on kinetics of P700 redox transients in cyanobacterium Arthrospira platensis cells. 1744 80