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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)
The effect of dichloroacetate on rates of gluconeogenesis was studied in isolated parenchymal cells obtained from the livers of normal fasted rats. Dichloroacetate significantly inhibited
glucose
formation from endogenous substrates and from added precursors (e.g., lactate, pyruvate, or glycerate) which enter the gluconeogenic pathway prior to the level of
glyceraldehyde-3-phosphate dehydrogenase
(GPDH). In contrast, dichloroacetate did not significantly affect
glucose
synthesis from precursors (e.g., fructose, or glycerol) which enter beyond the GPDH-catalyzed step. Lactate production from fructose of glycerol was unaffected by dichloroacetate. Inhibition of gluconeogenesis occurred regardless of the apparent effects of dichloroacetate on the redox state of the cytosol. Dichloroacetate produced variable effects on the lactate-pyruvate substate pair, while it consistently produced a more oxidized state in the beta-hydroxybutyrate--acetoacetate couple. Unlike uncoupling agents, dichloroacetate reduced
glucose
synthesis without stimulating respiration or altering total adenine nucleotide levels or ATP/ADP ratios. Dichloroacetate did not affect the metabolism of lactate or pyruvate to CO2 or glycogen. It did, however, significantly inhibit conversion by the cells of added lactate to pyruvate and
glucose
or of added pyruvate to lactate and
glucose
.
...
PMID:Effect of dichloroacetate on gluconeogenesis in isolated rat hepatocytes. 83 45
In biopsy samples of the lateral part of the quadriceps femoris muscle of 6 obese diabetic male patients and of 11 obese males with a normal
glucose
tolerance, the activities of 7 enzymes of energy metabolism were estimated: hexokinase, cytoplasmic glycerol-3-phosphate: NAD dehydrogenase,
triosephosphate dehydrogenase
, lactate dehydrogenase, citrate synthase, malate dehydrogenase and 3-hydroxyacyl-CoA dehydrogenase. The obese diabetic male patients exhibited decreased activities of enzymes of carbohydrate breakdown and cytoplasmic NAD regeneration. Enzymes connected functionally with aerobic metabolism were less affected. The unchanged activity of 3-hydroxyacyl-CoA dehydrogenase points to an increased role of fatty acid catabolism in the muscle.
...
PMID:Enzyme activities in quadriceps femoris muscle of obese diabetic male patients. 90 76
The selective metabolic effects of
glucose
and insulin were tested in an intact working swine heart preparation. Supplements of
glucose
(26.6 millimolar [mM] and insulin (0.025 units/ml) were provided to 18 hearts, 9 control hearts (coronary flow 151 ml/min) and 9 hearts rendered globally ischemic (coronary flow reduced from 167 to 85 ml/min). These hearts were compared with 14 additional hearts (6 control and 8 ischemic) given no supplements (
glucose
8.6 mM, no excess insulin). In hearts without supplements, ischemic significantly decreased mechanical performance, myocardial oxygen consumption, fatty acid oxidation and tissue high energy phosphate stores.
Glucose
consumption was reduced from 133 micromoles (mumol)/hr per g (before ischemia) to 58 mumol/hr per g (P less than 0.05), presumably from inhibition at
glyceraldehyde-3-phosphate dehydrogenase
. Data for control hearts with excess
glucose
and insulin were similar to data in control hearts without supplements except that
glucose
consumption and glycolytic flux were increased. Ischemia in treated hearts, as compared with untreated ischemic hearts, effected similar significant decreases in myocardial oxygen consumption, fatty acid oxidation and high energy phosphate stores and resulted in greater reductions in mechanical performance and in 10 minutes' less average survival time.
Glucose
consumption was reduced from 483 (before ischemia) to 242 mumol/hr per g (P less than 0.005) and inhibition at
glyceraldehyde-3-phosphate dehydrogenase
was again noted. Thus, excess carbohydrate and insulin hormone, when infused directly into the ischemic myocardium, did not provide an efficacious increase in either glycolytic flux or energy production. These findings suggest that an alternative explanation for the reported efficacy of
glucose
-insulin-potassium infusions must be sought.
...
PMID:Effects of excess glucose and insulin on glycolytic metabolism during experimental myocardial ischemia. 93 98
Failure of glycolysis to increase sufficiently to supply optimal levels of energy production in ischemic heart muscle is due in part to the cummulative restrainst of acidosis on rate-limiting enzymes, particularly
glyceraldehyde-3-phosphate dehydrogenase
. In an effort to modify this inhibition and salvage jeopardized myocardium, treatment with excess levels of pyruvate and tromethamine (Tris), designed to buffer intracellular hydrogen ion accumulations and improve the oxidation-reduction ratio, NAD+/NADH, was tested in 59 swine hearts in two separate preparations of global and regional ischemia. Global ischemia, per se, caused hemodynamic deterioration and shortened survival time (44.3 +/- 3.1 minutes). Myocardial oxygen consumption, fatty acid oxidation, and
glucose
uptake were all significantly (P less than 0.001) reduced as were estimates of glycolysis and tissue stores of creatine phosphate and ATP (P less than 0.01). Although treatment with Tris alone was inconclusive, administrations of pyruvate (40-50 mM) buffered with Tris (added directly into the coronary perfusate) effected an improvement in mechanical function and a significant prolongation in survival time (56.9 +/- 2.6 minutes. P less than 0.01). Glycogenolysis was enhanced and levels of key glycolytic intermediates were reduced, suggesting an acceleration of glycolytic flux. Excess levels of pyruvate (1.52 +/- 0.48 mumol/ml of coronary perfusate) provided added substrate for oxidation and led to a greater than 5-fold incrase in rates of pyruvate decarboxylation as compared to untreated ischemic hearts...
...
PMID:Effects of treatment with pyruvate and tromethamine in experimental myocardial ischemia. 95 68
Fifteen red cell enzyme activities of growth-retarded patients with and without growth hormone (GH) deficiency were investigated before and after GH administration. The 15 enzymes were Hexokinase, phosphoglucomutase,
glucose
phosphate, isomerase, phosphofructokinase, fructose diphosphate aldolase, glyceraldehyde-3-phosphae dehydrogenase, triosephosphate isomerase, 2,3-diphosphoglycerate mutase, 3-phosphoglycerate kinase, 3-phosphoglycerate mutase, enolase, pyruvate kinase, glycose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, glutathione reducase. Sixty-six subjects were studied: 30 normal control subjects (group N) and 36 patients (aged 5-23 years) with short stature. Complete endocrine evaluation showed 21 (group I) to have GH deficiency (10 patients with isolated GH deficiency) and 15 (group II) to have normal hypothalamic and pituitary function except for two patients with a moderate hypothyroidism. Both had been receiving thyroid hormone treatment for a long time before our studies. All 36 patients were treated with 2 mg human growth hormone intramuscularly for 7 days. Before GH treatment no significant difference was observed between hematologic data in group I (GH deficiency) and group II (no GH deficiency). After GH therapy there was a significant increase in reticulocyte count in both groups of patients with short stature. The mean pretreatment value in group I was 1.294% +/- 0.084 (SEM); the mean post-treatment value was 2.081% +/- 0.287 (SEM)< P less than 0.005. The mean pretreatment value in group II was 1.0% 0.184 (SEM); the mean post-treatment value was 1.407% +/- 0.193 (SEM), P less than 0.01. In group II (no GH deficiency) mean pretreatment erythrocyte enzyme activities were not significantly different from those activities observed in normal control subjects (group N). However, in patients who lacked GH, the pretreatment activities of five red cell enzymes (glucose phosphate isomerase, triosephosphate isomerase,
glyceraldehyde-3-phosphate dehydrogenase
, 2,3-diphosphoglycerate mutase, 3-phosphoglycerate kinase) were significantly decreased before GH administration compared with the values in normal control subjects...
...
PMID:Action of growth hormone on erythropoiesis: changes in red blood cell enzyme activities in growth-retarded patients with and without growth hormone deficiency. 95 53
1. The following enzyme activities were estimated in needle-biopsy samples of the lateral part of the human quadriceps femoris muscle:
triosephosphate dehydrogenase
(TPDH), lactate dehydrogenase (LDH), NAD : glycerol-3-phosphate dehydrogenase (GPDH), hexokinase (HK), NAD: malate dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase. 2. Although the enzyme activities in muscles of women were lesser than in those of men, no difference was found in the calculated enzyme activity ratios. There is thus no sex-dependent metabolic type-differentiation in this muscle. 3. The human quadriceps femoris is a low-activity muscle, in comparison with muscles of homoiotherm laboratory animals. The enzyme activity ratio of TPDH to CS, characterizing the glycolytic pyruvate formation to aerobic oxidative capacities, shows this muscle to be of an intermediate type in this respect, similarly as the extensor digitorum longus of the rat. The relatively very high capacity of
glucose
phosphorylation (HK), the high aerobic regeneration of cytoplasmic dehydrogenated NAD (GPDH) and the very low anaerobic regeneration (LDH), show the unusually high proportion of carbohydrates (
glucose
) which can be broken down aerobically.
...
PMID:M. Quadriceps femoris of man, a muscle with an unusual enzyme activity pattern of energy supplying metabolism in mammals. 116 80
A patient with hereditary spherocytosis (HS) was found to have
glyceraldehyde-3-phosphate dehydrogenase
(
G3PD
) deficiency by electrophoresis of the isolated red cell membranes on polyacrylamide gels with sodium dodecyl sulfate (PAGE SDS) as demonstrated by a diminished band 6 (
G3PD
) and confirmed by specific enzyme assay. Thirteen members of his family were studied: four were normal, two had HS alone, three had
G3PD
deficiency alone, and four had both HS and
G3PD
deficiency.
G3PD
deficient kindred members were probably heterozygous, since their red cell enzyme, while qualitatively normal, was present in half normal amounts. The
G3PD
deficiency alone was asymptomatic, and there was no evidence that the combination of HS with
G3PD
deficiency increased the clinical severity of the disease. However,
G3PD
deficiency, when combined with HS, was associated with an increase in protein band 4.5 on PAGE SDS. This band was also increased by incubation of normal red cells without
glucose
, and appeared to be a protein absorbed to the membrane as a consequence of metabolic stress. Hence, red cells with the combined abnormalities of both HS and
G3PD
deficiency showed signs of the exceptional metabolic stress to which they were exposed.
...
PMID:Study of a kindred with hereditary spherocytosis and glyceraldehyde-3-phosphate dehydrogenase deficiency. 124 16
Gold-labeled antibodies were used to examine the subcellular locations of 11 glycolytic and fermentative enzymes in Zymomonas mobilis.
Glucose
-fructose oxidoreductase was clearly localized in the periplasmic region. Phosphogluconate lactonase and alcohol dehydrogenase I were concentrated in the cytoplasm near the plasma membrane. The eight remaining enzymes were more evenly distributed within the cytoplasmic matrix. Selected enzyme pairs were labeled on opposite sides of the same thin section to examine the frequency of colocalization. Results from these experiments provide evidence that
glyceraldehyde-3-phosphate dehydrogenase
, phosphoglycerate kinase, and alcohol dehydrogenase I form an enzyme complex.
...
PMID:Immunocytochemical localization of glycolytic and fermentative enzymes in Zymomonas mobilis. 132 Jun 11
Northern-blot analysis was used to demonstrate that an increase in extracellular
glucose
concentration increased the content of preproinsulin mRNA 2.3-fold in the beta-cell line HIT T15. A probe for the constitutively expressed
glyceraldehyde-3-phosphate dehydrogenase
was used as a control. Mannoheptulose blocked this effect of
glucose
. A stimulatory effect on preproinsulin mRNA levels was also observed in response to mannose and to 4-methyl-2-oxopentanoate. However, galactose and arginine were ineffective. Glucagon, forskolin and dibutyryl cyclic AMP also elicited an increase in HIT-cell preproinsulin mRNA. The ability of the 5' upstream region of the preproinsulin gene to mediate the effect of
glucose
and other metabolites on transcription was studied by using a bacterial reporter gene technique. HIT cells were transfected with a plasmid, pOK1, containing the upstream region of the rat insulin-1 gene (-345 to +1) linked to chloramphenicol acetyltransferase (CAT). Co-transfection with a plasmid pRSV beta-gal containing beta-galactosidase driven by the Rous sarcoma virus promoter was used as a control for the efficiency of transfection; expression of CAT activity in transfected HIT cells was normalized by reference to expression of beta-galactosidase.
Glucose
caused a dose-dependent increase in expression of CAT activity, with a half-maximal effect at 5.5 mM and a maximum response of 4-fold. Mannoheptulose blocked this effect of
glucose
. Other metabolites (mannose, 4-methyl-2-oxopentanoate and leucine plus glutamine) were also able to increase insulin promoter-driven CAT expression, but galactose and arginine were ineffective. The stimulatory effect of
glucose
on CAT expression was not blocked by verapamil and was inhibited by increasing extracellular Ca2+ from 0.4 to 5 mM. Both dibutyryl cyclic AMP and forskolin caused an increase in insulin promoter-driven gene expression in the presence of 1 mM-
glucose
, but neither agent further increased the level of expression occurring in the presence of a maximally stimulating
glucose
concentration. The phorbol ester phorbol 12-myristate 13-acetate (PMA) also increased insulin promoter-driven CAT expression in the presence of 1 mM-, but not 11 mM-
glucose
. Staurosporine blocked the stimulatory effect not only of PMA but also of
glucose
and of dibutyryl cyclic AMP. We conclude that the 5' upstream region of the insulin gene contains sequences responsible for mediating the stimulatory effect of
glucose
on insulin-gene transcription.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Control of insulin gene expression by glucose. 132 37
In order to obtain large quantities of extremely pure human asparagine synthetase for detailed kinetic and structural studies, its gene was cloned into a 2mu plasmid (pBS24.1GAS) suitable for replication in a Saccharomyces cerevisiae cir0 strain (AB116). In this construct, the transcription of the asparagine synthetase gene is regulated by the alcohol dehydrogenase II/
glyceraldehyde-3-phosphate dehydrogenase
promoter, which is subject to
glucose
repression. The expression of the enzyme was allowed to take place in yeast minimal medium containing D-galactose as the only sugar nutrient. Eleven monoclonal antibodies to recombinant human asparagine synthetase were produced and one of them was selected to make immunoaffinity resins. After single-step immunoaffinity chromatography, more than 1.2 mg of homogeneous enzyme was obtained from the total cell extract from a 100-ml yeast culture. The yield of pure enzyme was over 100-fold higher than that of a previously reported yeast expression system. SDS-PAGE analysis showed the enzyme to be extremely pure and isoelectric focusing gel electrophoresis showed that the enzyme has an isoelectric point of 7.5. Immunoaffinity-purified recombinant human asparagine synthetase demonstrated both glutamine-dependent and ammonia-dependent asparagine synthetase activities, as well as glutaminase activity.
...
PMID:High-level expression of human asparagine synthetase and production of monoclonal antibodies for enzyme purification. 135 3
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