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

The 11.5-kDa Zn(2+)-binding protein (ZnBP) was covalently linked to Sepharose. Affinity chromatography with a cytosolic subfraction from liver resulted in purification of a predominant 38-kDa protein. In comparable experiments with brain cytosol a 39-kDa protein was enriched. The ZnBP-protein interactions were zinc-specific. Both proteins were identified as fructose-1,6-bisphosphate aldolase. Experiments with crude cytosol showed zinc-specific interaction of additional enzymes involved in carbohydrate metabolism. From liver cytosol greater than 90% of the following enzymes were specifically retained: aldolase, phosphofructokinase-1, hexokinase/glucokinase, glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and fructose-1,6-bisphosphatase. Glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, and most of triosephosphate isomerase remained unbound. From L-type pyruvate kinase only the phosphorylated form seems to interact with ZnBP. Using brain cytosol hexokinase, phosphofructokinase-1, and aldolase were completely bound to the affinity column, whereas glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, pyruvate kinase, and most of triose-phosphate isomerase remained unbound. The behavior of glucose-6-phosphate dehydrogenase and glycerol-3-phosphate dehydrogenase from this tissue could not be followed. A possible function of ZnBP in supramolecular organization of carbohydrate metabolism is proposed.
 ...
PMID:Key enzymes of carbohydrate metabolism as targets of the 11.5-kDa Zn(2+)-binding protein (parathymosin). 183 54

Three transposon Tn5-induced mutants deficient in autotrophic CO2 fixation were isolated from a megaplasmid pHG1-cured strain of Alcaligenes eutrophus H16. Their phenotypes were initially characterized by their ability to form both key enzymes of the Calvin cycle, ribulose-1,5-bisphosphate carboxylase (Rubisco) and phosphoribulokinase (PRK). Since the transposon insertions were at different sites within the chromosomal cluster of cfx genes encoding Calvin cycle enzymes, the individual mutants showed different inactivation patterns for Rubisco and PRK synthesis. These data together with already known sequence data and the arrangement of cfx genes suggested that the Rubisco, fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase and PRK genes are constituents of the same operon. This was further confirmed by trans complementation analyses which indicated that the very similarly organized pHG1-encoded cfx genes additionally present in wild-type strain H16 are functional and also form a common operon. Each operon may also include a glyceraldehyde-3-phosphate dehydrogenase gene. Thus, the duplicated cfx operons of A. eutrophus H16 are large transcriptional units comprising at least about 8 kilobase pairs (kb) and possibly as much as 11 kb.
 ...
PMID:On the operon structure of the cfx gene clusters in Alcaligenes eutrophus. 216 96

Cathepsins M and B from rabbit liver lysosomes were separated by chromatography on Ultrogel AcA34 at low ionic strength and purified to homogeneity, and their catalytic and molecular properties were compared. Cathepsin M was relatively inactive with synthetic peptide substrates. Thus, it hydrolyzed benzoyl arginine naphthylamide at only one-fifth the rate observed with cathepsin B, and no activity was detected with Gly-Phe naphthylamide which is a relatively good substrate for cathepsin B. On the other hand, cathepsin M exhibited a preference for protein substrates. It was more active than cathepsin B in catalyzing the inactivation of the following enzymes: rabbit muscle or liver fructose-1,6-bisphosphate aldolases, rabbit liver fructose-1,6-bisphosphatase and pyruvate kinase, yeast glucose-6-phosphate dehydrogenase, and rabbit muscle glyceraldehyde-3-phosphate dehydrogenase. With glucagon as substrate, both enzymes showed similar peptidyl dipeptidase activities with some minor differences in peptide bond specificity. Cathepsins M and B are similar in size, with apparent molecular weights of 30,200 for cathepsin M and 28,800 for cathepsin B, and in amino acid composition and carbohydrate content. Each contains approximately 2-3 equivalents/mol glucosamine, 3 equivalents/mol mannose, and no fucose or galactosamine. They also show similar microheterogeneity in sodium dodecylsulfate-gel electrophoresis and isoelectric focusing; this microheterogeneity is probably related to differences in glycosylation. Extensive homology in primary structure for the two proteins was indicated by the similar patterns of peptides formed on digestion with trypsin.
 ...
PMID:Purification and properties of rabbit liver cathepsin M and cathepsin B. 406 7

Rat liver enzymes were used to study the relationship between their in vivo half-lives and their apparent hydrophobicity or their resistance to inactivation by mechanical shaking. The apparent hydrophobicity of these enzymes, measured as the percent of the protein recovered from an octyl-Sepharose column, is correlated with their known half-lives (r = 0.75, P less than 0.01). The presence of specific ligands which are known to increase compactness by impeding unfolding of proteins decreased the apparent hydrophobicity of fructose-1,6-bisphosphatase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase. Resistance of enzymes to inactivation by mechanical shaking correlated well with their in vivo half-lives (r = 0.90, P less than 0.01). When the shaking experiments were done in the presence of substrates, fructose-1,6-bisphosphatase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase were protected from inactivation.
 ...
PMID:Protein hydrophobicity and stability support the thermodynamic theory of protein degradation. 633 12

It has been shown that inactivation of several enzymes precedes overall conformational changes of the enzyme molecules as a whole during denaturation [Tsou (1993) Science, 262, 380-381]. However, the relation between inactivation, loss of allosteric properties of oligomeric enzymes and unfolding of the enzyme molecule during denaturation remain little explored. These have now been compared for D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and fructose-1,6-bisphosphatase (FruP2ase) during denaturation by guanidinium chloride (GdmCl). GAPDH is completely inactivated at 0.3 M GdmCl but at this GdmCl concentration it still binds NAD+ with negative co-operativity. At 0.4 M GdmCl, inactivation of FruP2ase reaches completion whereas its allosteric properties, including the heterotropic effect of AMP inhibition and K+ activation with positive co-operativity, are only partially affected. Much higher GdmCl concentrations are required to bring about unfolding of the overall structures of both enzymes.
 ...
PMID:Inactivation precedes changes in allosteric properties and conformation of D-glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphatase during denaturation by guanidinium chloride. 794 47

Methanococcus maripaludis, a facultatively autotrophic archaebacterium that grows with H2 or formate as the electron donor, does not assimilate sugars and other complex organic substrates. However, glycogen is biosynthesized intracellularly and commonly reaches values of 0.34% of the cellular dry weight in the early stationary phase. To determine the pathway of glycogen catabolism, specific enzymes of sugar metabolism were assayed in cell extracts. The following enzymes were found (specific activity in milliunits per milligram of protein): glycogen phosphorylase, 4.4; phosphoglucomutase, 10; glucose-6-phosphate isomerase, 9; 6-phosphofructokinase, 5.6, fructose-1,6-bisphosphatase, 10; fructose-1,6-bisphosphate aldolase, 4.2; triosephosphate isomerase, 44; glyceraldehyde-3-phosphate dehydrogenase, 26; phosphoglycerate kinase, 20; phosphoglycerate mutase, 78; enolase, 107; and pyruvate kinase, 4.0. Glyceraldehyde-3-phosphate dehydrogenase was NADP+ dependent, and the pyruvate kinase required MnCl2. The 6-phosphofructokinase had an unusually low pH optimum of 6.0. Four nonoxidative pentose-biosynthetic enzymes were found (specific activity in milliunits per milligram of protein): transketolase, 12; transaldolase, 24; ribulose-5-phosphate-3-epimerase, 55; and ribulose-5-phosphate isomerase, 100. However, the key enzymes of the oxidative pentose phosphate pathway, the reductive pentose phosphate pathway, and the classical and modified Entner-Duodoroff pathways were not detected. Thus, glycogen appears to be catabolized by the Embden-Meyerhoff-Parnas pathway. This result is in striking contrast to the nonmethanogenic archaebacteria that have been examined, among which the Entner-Doudoroff pathway is common. A dithiothreitol-specific NADP(+)-reducing activity was also found (8.5 mU/mg of protein). Other thiol compounds, such as cysteine hydrochloride, reduced glutathione, and 2-mercaptoethanesulfonic acid, did not replace dithiothreitol for this activity. The physiological significance of this activity is not known.
 ...
PMID:Pathway of glycogen metabolism in Methanococcus maripaludis. 828 25

We analyzed antioxidative defenses, photosynthesis, and pigments (especially xanthophyll-cycle components) in two wheat (Triticum durum Desf.) cultivars, Adamello and Ofanto, during dehydration and rehydration to determine the difference in their sensitivities to drought and to elucidate the role of different protective mechanisms against oxidative stress. Drought caused a more pronounced inhibition in growth and photosynthetic rates in the more sensitive cv Adamello compared with the relatively tolerant cv Ofanto. During dehydration the glutathione content decreased in both wheat cultivars, but only cv Adamello showed a significant increase in glutathione reductase and hydrogen peroxide-glutathione peroxidase activities. The activation states of two sulfhydryl-containing chloroplast enzymes, NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphatase, were maintained at control levels during dehydration and rehydration in both cultivars. This indicates that the defense systems involved are efficient in the protection of sulfhydryl groups against oxidation. Drought did not cause significant effects on lipid peroxidation. Upon dehydration, a decline in chlorophyll a, lutein, neoxanthin, and beta-carotene contents, and an increase in the pool of de-epoxidized xanthophyll-cycle components (i.e. zeaxanthin and antheraxanthin), were evident only in cv Adamello. Accordingly, after exposure to drought, cv Adamello showed a larger reduction in the actual photosystem II photochemical efficiency and a higher increase in nonradiative energy dissipation than cv Ofanto. Although differences in zeaxanthin content were not sufficient to explain the difference in drought tolerance between the two cultivars, zeaxanthin formation may be relevant in avoiding irreversible damage to photosystem II in the more sensitive cultivar.
 ...
PMID:Antioxidative defense system, pigment composition, and photosynthetic efficiency in two wheat cultivars subjected to drought 1006 48

Low temperature inhibits sucrose synthesis, leading to a phosphate-limitation of photosynthesis. We have used the Arabidopsis pho1-2 and pho2-1 mutants with decreased and increased shoot phosphate, respectively, to investigate whether low phosphate triggers cold acclimatization of photosynthetic carbon metabolism. Wild-type Arabidopsis, pho1-2 and pho2-1 were grown at 23 degrees C and transferred to 5 degrees C to investigate acclimatization in pre-existing leaves and in new leaves developing at 5 degrees C. The development of frost tolerance and the accumulation of proline and sugars was unaltered or improved in pho1-2, and impaired in pho2-1. Sucrose phosphate synthase and cytoplasmic fructose-1,6-bisphosphatase activity and protein increase after transfer to 5 degrees C. This increase was accentuated in pho1-2 and attenuated in pho2-1. RBCS and LHCB2 transcript levels decrease in pre-formed wild-type leaves after transfer to 5 degrees C and recover in new leaves that develop at 5 degrees C. The initial decrease was attenuated in pho1-2, and accentuated in pho2-1, where the recovery in new leaves was also suppressed. Rubisco activity increased in wild-type leaves that developed at 5 degrees C. This increase was accentuated in pho1-2 and absent in pho2-1. NADP-glyceraldehyde-3-phosphate dehydrogenase, plastidic fructose-1,6-bisphosphatase and aldolase activity increase relative to phosphoglycerate kinase, transketolase and phosphoribulokinase in wild-type leaves at 5 degrees C. This shift was accentuated in pho1-2 and reversed in pho2-1. Transcript levels for COR genes increase transiently 1 day after transfer to 5 degrees C but were very low in leaves that developed at 5 degrees C in wild-type Arabidopsis, pho1-2 and pho2-1. We conclude that low phosphate plays an important role in triggering cold acclimatization of leaves, leading in particular to an increase of Rubisco expression, changes in other Calvin cycle enzymes to minimize sequestration of phosphate in metabolites, and increased expression of sucrose biosynthesis enzymes.
 ...
PMID:The role of inorganic phosphate in the development of freezing tolerance and the acclimatization of photosynthesis to low temperature is revealed by the pho mutants of Arabidopsis thaliana. 1106 11

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.
 ...
PMID:Consequence of restricted mitochondrial oxidative metabolism on photosynthetic carbon assimilation in mesophyll protoplasts: Decrease in light activation of four chloroplastic enzymes. 1147 20

This study examined the influence of high light levels on antioxidant metabolism and the photosynthetic properties of Begonia x erythrophylla leaves. The pigment composition of shaded leaves and those developing in full sunlight was typical of shade- and sun-leaves, respectively. After 28 d in full sunlight, the preformed leaves of shade plants transferred to full sunlight (transferred-leaves) showed photo-bleaching with lower Chl (a + b) content and Chl a : Chl b ratios than shade-leaves, with Chl (a + b) : carotenoid ratios not significantly different. The variable/maximal fluorescence (Fv/Fm) of sun-leaves was not significantly different from that of shade-leaves, but transferred-leaves had reduced Fv : Fm ratios. Light response curves for the electron transport rate (ETR), the oxidation state of photosystem II (qP) and non-photochemical quenching (NPQ) showed significant differences between the three leaf types, with transferred-leaves not able to acclimate completely to full sunlight, having lower ETR, qP and NPQ values at high light levels than sun-leaves. Transfer to full sunlight caused a rapid increase in H2O2 and lipid hyperoxides, and a slight increase in protein oxidation. Ascorbate and glutathione levels decreased rapidly, as did the size of the total glutathione pool and, in addition to the general oxidation of proteins, rapid decreases in both the initial and total activities of chloroplastic fructose-1,6-bisphosphatase and glyceraldehyde-3-phosphate dehydrogenase were observed. These results suggest that a more oxidizing cellular environment is the likely cause of the photo-bleaching observed upon transfer of shade-leaves to full sunlight. Acclimation of transferred-leaves to full sunlight involved gradual increases in the activities of enzymes involved in antioxidant metabolism, including superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, dehydroascorbate reductase and monodehydroascorbate reductase, but the levels of these enzymes still remained at levels lower than those found in sun-leaves.
 ...
PMID:Antioxidant metabolism during acclimation of Begonia x erythrophylla to high light levels. 1273 64


1 2 3 4 Next >>