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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)
Cytosolic free magnesium (Mgf) is considered relatively constant. To test this concept, Mgf was estimated during hyperkalemic ventricular akinesis, normal and maximum adrenergic stimulation, and sulfate loading of the normoxic perfused guinea-pig heart. The Mgf estimates utilized a new sliding scale derived from the Mg(2+)-dependence of
glyceraldehyde-3-phosphate dehydrogenase
/phosphoglycerate kinase (
GAPDH
/PGK). The pseudo constant K'
GAPDH
.K'PGK was measured as ([creatine phosphate][3-phosphoglycerate][lactate]KLDH)/([creatine][Pi] [glyceraldehyde 3-phosphate][pyruvate]KCK), which varied with magnesium due to KCK (CK, LDH = creatine kinase, lactate dehydrogenase). However, the correct magnesium dependencies of the true constants KGAPDH.KPGK and KCK were taken from the literature. The [Mg2+] at which pseudo K'
GAPDH
.K'PGK equalled true KGAPDH.KPGK was the best estimate of Mgf.Mgf fell to approximately 0.13 mM in hyperkalemic arrest from a control of approximately 0.6 mM, rising to approximately 0.85 mM only during maximum adrenergic stress. Mgf increased further to approximately 1.3 mM during sulfate loading which induced ATP catabolism. Mgf and ATP were reciprocally related. Thus; (1) myocardial free [Mg2+] judged from
GADPH
/PGK mass-action relations changed appreciably only under extreme physiological states; (2) ATP was a major chelator of Mg2+ in perfused myocardium, i.e., acute ATP pool size reduction may be associated with increments in Mgf.
...
PMID:Use of cytosolic metabolite patterns to estimate free magnesium in normoxic myocardium. 162 62
We studied the possible relationships between the functional status of the beta-cell and activities or mRNA contents of enzymes involved in the catabolism of glucose. Three different in vitro models with attenuated insulin response were used: rat islets cultured at a low glucose concentration, rat islets incubated in vitro with streptozocin, and fetal rat islets. The fetal and streptozocin-administered islets were compared with adult islets cultured in RPMI-1640 containing 11 mM glucose, and the effects of the in vitro glucose concentrations (3.3, 11, and 28 mM) were assessed on adult islets only. Cellular mRNA levels for the mitochondrial DNA-encoded cytochrome b and
glyceraldehyde-3-phosphate dehydrogenase
(
GAPDH
) were determined by Northern-blot analysis. Enzymatic activities of high-Km (glucokinase) and low-Km (hexokinase) glucose-
phosphorylating
enzymes and succinate-cytochrome c reductase were also determined. Islets cultured at 3.3 mM glucose displayed a decreased activity of glucokinase compared with islets cultured at 28 mM glucose (23.3 +/- 12%), whereas there was no difference in hexokinase activity or the level of
GAPDH mRNA
. The activity of succinate-cytochrome c reductase was similar in islets cultured at the different glucose concentrations. The level of cytochrome b mRNA increased at 28 mM glucose compared with islets cultured at 11 mM glucose (140 +/- 14%). Islets incubated with streptozocin and subsequently cultured for 7 days at 11 mM glucose exhibited a decreased level of cytochrome b mRNA (65 +/- 5%) and no differences in the activities of glucokinase, hexokinase, succinate-cytochrome c reductase, or the level of
GAPDH mRNA
.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Exhibition of specific alterations in activities and mRNA levels of rat islet glycolytic and mitochondrial enzymes in three different in vitro model systems for attenuated insulin release. 164 83
Chronic exposure of differentiated avian skeletal muscle cells in culture to the phorbol ester, 12-O-tetradecanoyl phorbol-13-acetate (PMA), results in the selective disassembly of sarcomeric structures and loss of muscle-specific contractile proteins, leaving cytoskeletal structures and their associated proteins intact. We demonstrate here that these morphological and biochemical changes are accompanied by dramatic and selective decreases in the level of the mRNAs that encode the contractile proteins. We measured the effects of PMA on the transcriptional activity and mRNA stability of four contractile protein genes (alpha-cardiac and alpha-skeletal actin, cardiac troponin C [cTnC], and myosin light chain lf [MLClf]) and two nonmuscle genes (beta-cytoplasmic actin and the glycolytic enzyme,
glyceraldehyde-3-phosphate dehydrogenase
[
GAPDH
]). The transcriptional activity of the alpha-cardiac actin and cTnC genes dramatically decreased by 8 h after the addition of PMA, while other muscle and nonmuscle genes examined showed no change. Pulse-chase experiments of in vivo labeled RNA showed significant reductions in mRNA half-lifes for all the contractile protein mRNAs examined, while the half-lifes of beta-actin and
GAPDH mRNA
were unchanged. All of the above effects occurred under conditions in which cellular protein kinase C (PKC) levels had been reduced by greater than 90%. The fact that many of the contractile protein genes remained transcriptionally active despite the fact that the cells were unable to accumulate their mRNAs to any significant extent indicated that the treated cells were still committed to skeletal muscle differentiation. The selective changes in the stability of the contractile protein mRNAs suggest that the control of mRNA stability may be part of the normal regulatory program of skeletal muscle differentiation and that this control may be linked to the integrity of the contractile apparatus and mediated by second messenger pathways involving PKC activation.
...
PMID:Phorbol esters selectively downregulate contractile protein gene expression in terminally differentiated myotubes through transcriptional repression and message destabilization. 171 91
We have isolated and characterized a plasmid (pChug 20.1) that contains the cDNA of a nuclear
uracil DNA glycosylase
(
UDG
) gene isolated from normal human placenta. This cDNA directed the synthesis of a fusion protein (Mr 66,000) that exhibited
UDG
activity. The enzymatic activity was specific for a uracil-containing polynucleotide substrate and was inhibited by a glycosylase antibody or a beta-galactosidase antibody. Sequence analysis demonstrated an open reading frame that encoded a protein of 335 amino acids of calculated Mr 36,050 and pI 8.7, corresponding to the Mr 37,000 and pI 8.1 of purified human placental
UDG
. No homology was seen between this cDNA and the
UDG
of herpes simplex virus, Escherichia coli, and yeast; nor was there homology with the putative human mitochondrial
UDG
cDNA or with a second human nuclear
UDG
cDNA. Surprisingly, a search of the GenBank data base revealed that the cDNA of
UDG
was completely homologous with the 37-kDa subunit of human
glyceraldehyde-3-phosphate dehydrogenase
. Human erythrocyte
glyceraldehyde-3-phosphate dehydrogenase
was obtained commercially in its tetrameric form. A 37-kDa subunit was isolated from it and shown to possess
UDG
activity equivalent to that seen for the purified human placental
UDG
. The multiple functions of this 37-kDa protein as here and previously reported indicate that it possesses a series of activities, depending on its oligomeric state. Accordingly, mutation(s) in the gene of this multifunctional protein may conceivably result in the diverse cellular phenotypes of Bloom syndrome.
...
PMID:A human nuclear uracil DNA glycosylase is the 37-kDa subunit of glyceraldehyde-3-phosphate dehydrogenase. 192 5
Glucocorticoids modulate various cellular functions such as proliferation, energy metabolism and the synthesis of proteins. In the present study, the response of collagen genes to dexamethasone in different stages of chick embryo development was studied in tendon and heart using Northern blot analysis and specific cDNA probes. The changes in collagen gene expression were compared to alterations in two reference mRNAs: actin and
glyceraldehyde-3-phosphate dehydrogenase
(
GAPDH
). The levels of specific mRNAs measured per ribosomal RNA in tendon and heart varied markedly during normal development. In tendon the relative levels of alpha 1(I), alpha 2(I) and alpha 1(III) collagen mRNAs were highest between days 14-16 when also the synthesis of matrix proteins is most active. In heart the levels of these mRNAs peaked at day 12. In addition, qualitative differences were observed in the expression of actin genes between tendon and heart. Dexamethasone in high dose decreased collagen mRNA levels in tendons, while in heart a stimulatory effect was noted. Dexamethasone also decreased
GAPDH mRNA
levels in tendons. The alterations in gene expression after dexamethasone treatment in tendon and heart did not correlate with the level of specific glucocorticoid receptors, which varied markedly during the development of chick embryos. The cDNA for pro alpha 1(I) collagen hybridized to two transcripts corresponding to 6.2 and 5.1 kb in tendon and heart. During normal development of chick embryos the ratio of 6.2/5.1 kb mRNAs decreased markedly in heart, but no such change was observed in tendons. Dexamethasone, however, decreased the ratio of 6.2/5.1 kb transcripts in tendons. There was a significant correlation between the ratio 6.2/5.1 kb transcripts and total alpha 1(I) mRNA both in tendon and heart, suggesting that the 6.2 kb transcript may be associated with the rate of synthesis of type I collagen.
...
PMID:Comparison on collagen gene expression in the developing chick embryo tendon and heart. Tissue and development time-dependent action of dexamethasone. 202 46
The combination of binding and kinetic approaches is suggested to study (i) the mechanism of substrate-modulated dynamic enzyme associations; (ii) the specificity of enzyme interactions. The effect of complex formation between aldolase and
glyceraldehyde-3-phosphate dehydrogenase
(D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (
phosphorylating
), EC 1.2.1.12) on aldolase catalysis was investigated under pseudo-first-order conditions. No change in kcat but a significant increase in KM of fructose 1,6-bisphosphate for aldolase was found when both enzymes were obtained from muscle. In contrast, kcat rather than KM changed if dehydrogenase was isolated from yeast. Next, the conversion of fructose 1-phosphate was not affected by interactions between enzyme couples isolated from muscle. The influence of fructose phosphates on the enzyme-complex formation was studied by means of covalently attached fluorescent probe. We found that the interaction ws not perturbed by the presence of fructose 1-phosphate; however, fructose 1,6-bisphosphate altered the dissociation constant of the enzyme complex. A molecular model for fructose 1,6-bisphosphate-modulated enzyme interaction has been evaluated which suggests that high levels of fructose bisphosphate would drive the formation of the 'channelling' complex between aldolase and
glyceraldehyde-3-phosphate dehydrogenase
.
...
PMID:Cooperative effect of fructose bisphosphate and glyceraldehyde-3-phosphate dehydrogenase on aldolase action. 210 14
Tissue culture for one or seven days of pancreatic islets isolated from 21-day old fetal rats was found to be associated with a marked increase in the oxidation of L-(U-14C) glutamine by intact islets and in the activity of both alanine-glutamate and aspartate-glutamate transaminases as well as glutamate dehydrogenase in islet homogenates. This coincided with an increase in the relative amount of mitochondrial DNA. The activities of glucose-
phosphorylating
enzymes (hexokinase and glucokinase),
glyceraldehyde-3-phosphate dehydrogenase
and lactate dehydrogenase were less markedly increased during the culture period than those of enzymes involved in amino acid catabolism and located, in part at least, in mitochondria. The combined data suggest that the functional maturation of fetal islets during the culture period is associated with and may be attributable to a preferential maturation of their mitochondria.
...
PMID:Maturation of fetal rat islet cells in vitro during tissue culture is associated with increased mitochondrial function. 213 6
A cDNA library was constructed using mRNA from interleukin 2 (IL2)-stimulated cloned murine T lymphocytes to isolate cDNA clones of mRNAs that were induced by IL2 and present at maximal levels in late G1/early S phase of the cell cycle. When the library was screened by differential hybridization, over half of the clones isolated were found to cross-hybridize, indicating that there was a predominant IL2-induced mRNA in these cells. This cDNA was identified as encoding murine
glyceraldehyde-3-phosphate dehydrogenase
(
GAPDH
; EC 1.2.1.12). The in vitro translation product of this cDNA was a 36-kDa protein using both hybridization-selected RNA and in vitro transcribed RNA. We estimate that
GAPDH mRNA
comprises approx. 0.7% of total mRNA in the cloned T cells in late G1.
GAPDH mRNA
is induced two- to fivefold over resting levels upon IL2 stimulation, due in part to an increased rate of transcription.
GAPDH
enzymatic activity is induced approx. sevenfold over resting levels. The induction of
GAPDH mRNA
is inhibited only slightly by CHX under conditions in which cell proliferation is inhibited. In addition, the induction of
GAPDH
is directly due to the effect of IL2, and not in conjunction with any serum components, since IL2 will induce
GAPDH mRNA
under serum-free conditions. Finally, when genomic DNA is probed with a full-length
GAPDH
cDNA, a complex pattern of bands is observed, whereas if a 5' end probe is used, a much simpler pattern is obtained, indicating that many of the
GAPDH
pseudogenes in the murine genome lack 5' sequence information.
...
PMID:Glyceraldehyde-3-phosphate dehydrogenase mRNA is a major interleukin 2-induced transcript in a cloned T-helper lymphocyte. 214 97
The influence of limited oxidation of
glyceraldehyde-3-phosphate dehydrogenase
(D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (
phosphorylating
), EC 1.2.1.12), alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) and myoglobin by singlet oxygen and by hydroxyl radicals was investigated. The intrinsic fluorescence of
glyceraldehyde-3-phosphate dehydrogenase
and alcohol dehydrogenase decreased rapidly during oxidation, indicating a conformational change of the protein molecules. The free energy of isothermal unfolding in urea solutions was increased by singlet oxygen, but decreased by hydroxyl radical attack. The velocity of refolding of the denatured protein after dilution of the denaturant was increased by exposure to either singlet oxygen or hydroxyl radicals, with one exception: the velocity of refolding of myoglobin, oxidized by singlet oxygen, was strongly decreased. Hydroxyl radicals produced covalently crosslinked protein aggregates and some fragmentation, whereas singlet oxygen produced only crosslinked aggregates with
glyceraldehyde-3-phosphate dehydrogenase
and alcohol dehydrogenase. All oxidized proteins were more susceptible to proteolysis by elastase and proteinase K, as compared to the undamaged proteins. Singlet oxygen-induced crosslinked aggregates were degraded very rapidly by elastase. Hydroxyl radical-induced aggregates of
glyceraldehyde-3-phosphate dehydrogenase
were also degraded very rapidly by this enzyme, but hydroxyl radical-induced aggregates of alcohol dehydrogenase were resistent to enzymatic degradation. The results indicate that limited protein oxidation may have a pronounced influence on several properties of the protein. The effects vary, however, with varying proteins and with the oxidizing species.
...
PMID:Protein damage, induced by small amounts of photodynamically generated singlet oxygen or hydroxyl radicals. 215 21
Two independent cis-acting insulin response elements (IREs) in the gene encoding
glyceraldehyde-3-phosphate dehydrogenase
[D-glyceraldehyde-3-phosphate: NAD+ oxidoreductase (
phosphorylating
), EC 1.2.1.12], designated IRE-A and IRE-B, are sufficient to direct insulin-inducible gene expression. Using the electrophoretic mobility shift assay, a 4-fold increase in the amount of IRE-A DNA bound to nuclear proteins was detected when extracts isolated from insulin-stimulated differentiated 3T3-L1 cells or from the liver of rats refed a high-carbohydrate/low-fat diet after a 72-hr fast were compared to control nuclear extracts. The points of contact between protein and IRE-A DNA may represent a sequence recognized by at least one class of insulin-sensitive transcription factor(s).
...
PMID:An insulin response element in the glyceraldehyde-3-phosphate dehydrogenase gene binds a nuclear protein induced by insulin in cultured cells and by nutritional manipulations in vivo. 216 73
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