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At least 253 records · Page 14Linked to original sources
PubMed2000

Properties and stability of glycerophosphate oxidase isolated from a mutant strain of Aerococcus viridans.

The properties of microbial L-alpha-glycerophosphate oxidase (GPO) isolated from a mutant strain of Aerococcus viridans DBM 1509 were estimated. The stability at different temperatures and pH were detected. At 4 degrees C the enzyme lost activity during 15 d, at 20 degrees C and 30 degrees C GPO activity decreased during 30 and 25 h, respectively. The highest stability was measured at - 20 degrees C and pH 9. At 4 degrees C the stability was enhanced by the addition of 0.1 M EDTA or by lyophilization in the presence of dextrin. These conditions allow the prolongation of the low stability of microbial GPO which limited its use, and give the opportunity to increase the stability of other enzymes

Dextrins↗
PubMed1990

Effect of triiodothyronine and thyroxine on mitochondrial alpha-glycerophosphate dehydrogenase activity and mitochondrial protein content of liver, muscle and brain of toad, Bufo melanostictus.

The responsiveness of the adult toad to triiodothyronine (T3) and thyroxine (T4) was studied by measuring the mitochondrial alpha-glycerophosphate dehydrogenase activity and mitochondrial protein content of liver, muscle and brain of toad. Both T3 and T4 increased the alpha-GPD activity and mitochondrial protein content of liver and muscle of toad. The extent of increase in the alpha-GPD activity and mitochondrial protein content were more pronounced with T3 than with T4. Further that the muscle exhibited more alpha-GPD activity than liver, whenever liver showed greater mitochondrial protein content than that of muscle. Brain showed no significant change in the alpha-GPD activity and mitochondrial protein content. Injections of cycloheximide showed inhibition of T3 induced changes in liver and muscle. Injection of propylthiouracil also counteracted the T4 induced effects of liver and muscle.

Animals↗
PubMed1986

Amiodarone inhibits T4 to T3 conversion and alpha-glycerophosphate dehydrogenase and malic enzyme levels in rat liver.

Amiodarone has been found to decrease serum T3 by blocking peripheral T4 5'-deiodinase. This reduction in T3 levels may contribute to the effectiveness of this drug in moderating cardiac arrhythmias. To further characterize the effect of amiodarone on thyroid hormone metabolism and biological action, male Sprague-Dawley rats were thyroidectomized and then fed 500 ug T4 or 50 ug T3 and 500 mg amiodarone/kg of powdered diet for 6 to 8 weeks. Hepatic and cardiac levels of T4, T3, alpha-glycerophosphate dehydrogenase (GPD) and malic enzyme (ME) were used as indicators of thyroid hormone availability and action at the cellular level. Conversion of T4 to T3 was measured in liver homogenates. Serum TSH, T4 and T3 were also measured. Amiodarone reduced hepatic GPD and ME in thyroidectomized rats receiving dietary T4. Liver T4 levels were significantly increased by amiodarone and the T3/T4 ratio was reduced (P less than .05). Amiodarone inhibited hepatic T4 to T3 conversion and decreased serum T3. The decreased T3 action at the cellular level, indicated by the reduction in hepatic GPD and ME, is not due to pharmacologic effects of amiodarone since these enzyme levels were not affected by amiodarone in thyroidectomized rats replaced with T3.

Amiodarone↗
PubMed1997

Low mitochondrial glycerophosphate dehydrogenase activity in lymphocytes of women with gestational diabetes.

An abnormally low activity of mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH), relative to the paired measurement of glutamate dehydrogenase, was found in CD3+ lymphocytes from 4 out of 14 mothers with gestational diabetes mellitus, but in none of 36 control mothers. The low m-GDH activity coincided with an abnormally high incidence of familial history for non-insulin-dependent diabetes. These findings are compatible with the view that an inherited or acquired defect of m-GDH may participate to the pathogenesis of beta-cell dysfunction in a subgroup of patients with gestational diabetes.

Adult↗
PubMed1996

Ontogeny of FAD-linked glycerophosphate dehydrogenase in rat pancreatic islets.

The activities of the mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH), glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, glutamate-pyruvate transaminase (GPT) and glutamate-oxaloacetate transaminase were measured in islet and liver homogenates from fetal, neonatal, adult male, adult female, pregnant and lactating rats. Either parallel or dissociated ontogenic changes were observed in islet and liver homogenates. The activity of islet m-GDH was slightly, albeit not significantly, lower in neonates than in adult rats, comparable in male and female adult animals, unaffected by pregnancy, and increased during lactation. It was much higher in fetal or adult islets cultured for 7 days than in freshly isolated islets from adult rats. In cultured islets from adult rats, the increase in m-GDH activity coincided with a dramatic decrease of GPT activity, a situation the mirror image of that found in several animal models of non-insulin-dependent diabetes mellitus. The intrinsic properties of m-GDH, as judged by comparison of measurements made by either a radioisotopic or a colorimetric procedure, were not identical in islet and liver homogenates and differed between fetal and adult islets, suggesting the existence of distinct iso-enzymes. These findings illustrate adaptive changes of islet enzymes, with exclusive or partial mitochondrial location, in ontogenic situations characterized by a remodelling of fuel homeostasis.

Animals↗
PubMed1977

Microcomplement fixation studies on the evolution of alpha-glycerophosphate dehydrogenase within the genus Drosophila.

Antisera were prepared against purified alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) (alphaGPDH) from Drosophila melanogaster, D. virilis, and D. busckii. The immunological distances between the enzymes from the 3 species and those from 31 additional drosophilid species agree in general with the accepted phylogeny of the genus. These data permit an estimate that the subgenus Sophophora diverged 52 million years ago from the line leading to the subgenus Drosophila. The antiserum against melanogaster alphaGPDH was capable of distinguishing allelic variants of alphaGPDH. On the basis of presumed single amino acid substitutions, no drosophilid alphaGPDH tested differed from the melanogaster enzyme by more than eight or nine substitutions. The study was extended to include representatives of six other dipteran families. The immunological distances between alphaGPDH from Drosophila and alphaGPDH from these dipterans were reasonably consistent with a phylogeny of the order Diptera established by more conventional means. The unit evolutionary period of this enzyme was estimated to be 18 million years.

Animals↗
PubMed1979

A study of the adipose conversion of suspended 3T3 cells by using glycerophosphate dehydrogenase as differentiation marker.

The adipose conversion of 3T3 cells has been examined in stabilized suspension cultures. In 3T3-F442A cells, glycerophosphate dehydrogenase (sn-glycerol-3-phosphate: NAD(+) 2-oxidoreductase, EC 1.1.1.8), a key enzyme in triglyceride synthesis, increases in specific activity by more than 5000-fold and can be used as a sensitive and precise measure of the conversion. The conversion depends on an adipogenic factor present in the serum, and this factor can be assayed by the cellular enzyme response. If the cells are growing at the time they receive the adipogenic factor, the enzyme response does not become detectable until after 3 days, during which the cells first enter a resting state. If the cells are resting at the time they receive the adipogenic factor, the enzyme activity begins to increase in 24 hr or less. Only resting cells seem susceptible to the reprogramming of their differentiated state necessary for the adipose conversion. Once the conversion begins, the increase in enzyme activity is exponential over at least 2 orders of magnitude. When cells in a resting state begin the adipose conversion, their biosynthetic processes are accelerated: the rate of protein synthesis increases, they accumulate cell protein, and they may replicate their DNA and divide. The cell multiplication is not essential for adipose conversion but is a form of clonal selection that increases the proportion of adipose cells relative to nonadipose cells.

Adipose Tissue↗
PubMed2000

Identification of two transmembrane regions and a cytosolic domain of rat mitochondrial glycerophosphate acyltransferase.

The topography of rat glycerophosphate acyltransferase (GAT) in the transverse plane of the mitochondrial outer membrane (MOM) was investigated. Computer analysis of the amino acid (aa) sequence derived from rat mitochondrial GAT cDNA (GenBanktrade mark accession nos. and ) predicts the presence of two possible transmembrane domains (aa 473-493 and 574-594) separated by an 80-aa stretch (aa 494-573). To determine the actual orientation of the native protein, we prepared anti-peptide antibodies to three regions: one in between (aa 543-559) and the other two (aa 420-435 and 726-740) flanking the two putative transmembrane regions. Both immunoreaction and immunoprecipitation experiments employing intact and solubilized mitochondria indicate that regions on the N- and C-terminal sides of the transmembrane regions are sequestered on the inner surface of the MOM, while the region between the transmembrane domains is present on the cytosolic face of the MOM. Additionally, two green fluorescent protein (GFP) fusion proteins consisting of full-length GAT fused to GFP at either the C terminus or inserted 115 amino acids from the N terminus were also constructed to determine the orientation of the N and C termini. COS-1 cells expressing these fusion proteins were fractionated to obtain mitochondria. Protease digestion of intact and solubilized COS-1 cell mitochondria revealed that the GFP domains of these fusion proteins are sequestered on the inner side of the MOM. The present findings indicate that GAT is a dual-spanning, transmembrane protein adopting an inverted "U" conformation in the transverse plane of the MOM, where the N and C termini are sequestered on the inner surface of the MOM, while aa 494-573 are exposed on the cytosolic surface of the MOM.

Animals↗
PubMed1997

Changes in myocardial thyroid hormone metabolism and alpha-glycerophosphate dehydrogenase activity in rats deficient in iodine and selenium.

Weanling Wistar rats were fed on diets prepared from grain from areas deficient in I and Se where Keshan disease in endemic. Rats were divided into four groups, each of twelve rats, and received a diet supplemented with: I, Se, I + Se or nothing. At 8 weeks after weaning, myocardial alpha-glycerophosphate dehydrogenase (EC 1.1.1.8; alpha-GPD) activity and indices of Se and thyroid hormone status were determined. The group supplemented with iodine had increased plasma thyroxine levels. There was no difference in plasma triiodothyronine concentration between the groups but triiodothyronine levels in heart were reduced in the Se-supplemented group. Se supplementation increased myocardial glutathione peroxidase activity (EC 1.11.1.9) and the type I 5'-deiodinase (EC 3.8.1.4) activity in rat liver, but no type I 5'-deiodinase activity was detected in heart. alpha-GDP activity in heart was increased in group supplemented with Se, I or both. There was a significant relationship (P < 0.05) between myocardial alpha-GDP activity and plasma thyroxine levels but not between alpha-GDP and myocardial glutathione peroxidase activity. The results indicate that iodine may be more important than Se in energy metabolism in the myocardium, which may give a new insight for the study of the aetiology of Keshan disease in areas where foodstuffs are deficient in both Se and I.

Analysis of Variance↗
PubMed1969

Unusually high mitochondrial alpha glycerophosphate dehydrogenase activity in rat brown adipose tissue.

Brown adipose tissue of the rat has been found to have an unusually high activity of mitohondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) when assayed both by a histochemical staining procedure and by a quantitative biochemical method with isolated mitochondria. In contrast to succinic, glutamic, and beta-hydroxybutyrate dehydrogenases, all mitochondrial enzymes, the activity of alpha-GPD in brown fat was 10 times that in liver, more than 20 times that in white adipose tissue, and 9 times that in kidney. The soluble NAD-linked alpha-GPD was also higher in brown adipose tissue than in white adipose tissue, liver, or kidney, but the differences were much less marked. The possible importance of the high activity of mitochondrial alpha-GPD in the regulation of synthesis of esterified lipid and in thermogenesis in brown fat is discussed.

Adipose Tissue↗
PubMed1983

A cytogenetic analysis of the chromosomal region surrounding the alpha-glycerophosphate dehydrogenase locus of Drosophila melanogaster.

The chromosomal region surrounding the structural gene for alpha-glycerophosphate dehydrogenase (alpha Gpdh, 2-20.5) of Drosophila melanogaster has been studied in detail. Forty-three EMS-induced recessive lethal mutations and five previously identified visible mutations have been localized within the 25A-27D region of chromosome 2 by deficiency mapping and in some cases by a recombination analysis. The 43 lethal mutations specify 17 lethal loci. alpha Gpdh has been localized to a single polytene chromosome band, 25F5, and there apparently are no lethals that map to the alpha Gpdh locus.

Animals↗
PubMed1983

The characterization of alpha-glycerophosphate dehydrogenase mutants in Drosophila melanogaster.

Thirty mutants of alpha-glycerophosphate dehydrogenase (alpha GPDH, EC 1.1.1.8) from Drosophila melanogaster were produced with the chemical mutagen ethyl methanesulfonate (EMS). These mutants and nine others previously obtained have been characterized with respect to level of enzymatic activity, viability, flight ability, and presence of cross-reacting material (CRM). The presence of alpha GPDH mRNA in several of the mutans has been tested by in vitro translation. There are strong correlations between the level of enzyme activity, viability and flight ability. Thirteen of the mutants are CRM- by solution immunoprecipitation experiments, but of these, only three are CRM- by a more sensitive 125I-protein A-based radioimmune gel assay. The viability of the three CRM- mutants suggests that the absence of alpha GPDH protein is not a lethal condition. The immunoprecipitated protein of the low activity mutant, alpha GpdhnGL3, has a smaller apparent molecular weight on polyacrylamide-SDS gels than does the protein from wild type. Criteria for the identification of nonsense mutations in Drosophila are discussed.

Animals↗
PubMed1976

Hidden alleles at the alpha-glycerophosphate dehydrogenase locus in Colias butterflies.

By varying polyacrylamide gel pore size, the alpha-glycerophosphate dehydrogenase locus of Colias butterflies is shown to contain at least five alkeles, rather than the two which had been reported previously. Two of the alleles have the same apparent net charge, and presumably are detected electrophoretically because of the conformational differences. Additional variation occurs in the isoelectric points of the proteins. It is suggested that electrophoresis employing a single gel of intermediated pore size will fail to discriminate between many alleles, and that the concept of electrophoretic alleles as differing simply in charge may not always be appropriate.

Alleles↗
PubMed1986

Differential effect of phosphatidylethanolamine molecular species on glycerophosphate acyltransferase activity of Escherichia coli.

The effect of phosphatidylethanolamine (PE) molecular species on the reconstitution of partially purified glycerophosphate acyltransferase of Escherichia coli was investigated. The acyltransferase activity was abolished by 1,2-di-unsaturated (U-U) PE, but not by 1-saturated-2-unsaturated (S-U) PE or 1-saturated-2-cyclopropanoyl PE. Since both the U-U and S-U PE used in the present work are in a fluid state at temperatures above about 30 degrees C, the differential effect cannot be accounted for in terms of the membrane fluidity. Therefore, the inactivation of the reconstituted enzyme was attributed to the large amount of the 1,2-di-cis-vaccenoyl species of PE.

Acyltransferases↗
PubMed1995

Non-insulin-dependent diabetes mellitus and islet B-cell mitochondrial glycerophosphate dehydrogenase deficiency.

A deficient activity of the mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH) in the pancreatic islet B-cell may represent a contributing factor in the pathogenesis of non-insulin-dependent (Type 2) diabetes. This enzyme controls circulation in the glycerol phosphate shuttle and, hence, plays a key role in the B-cell glucose-sensing device. An impaired activity of this enzyme in pancreatic islets was documented in several, but not all, animal models of inherited or acquired non-insulin-dependent diabetes. Enzymatic studies conducted in lymphocytes or islets from diabetic patients, as well as a search for possible mutations of the m-GDH gene, were recently undertaken to extend these observations to human subjects.

Diabetes Mellitus, Type 2↗
PubMed1967

Alpha-glycerophosphate dehydrogenase and glucose-6-phosphate dehydrogenase in tissues of the Weddell seal.

High activity of alpha-glycerophosphate dehydrogenase and low activity of glucose-6-phosphate dehydrogenase in adipose tissue of Weddell seals suggest that neutral fat may be assembled there from exogenous sources of fatty acids. Low activity of glucose-6-phosphate dehydrogenase in other tissues tested precludes assignment of the function of fatty-acid synthesis to any specific tissue and emphasizes uniqueness of adipose mass in seals.

Adipose Tissue↗
PubMed1992

CDP-glycerol:poly(glycerophosphate) glycerophosphotransferase, which is involved in the synthesis of the major wall teichoic acid in Bacillus subtilis 168, is encoded by tagF (rodC).

Assays of CDP-glycerol:poly(glycerophosphate) glycerophosphotransferase (CGPTase) (EC 2.7.8.12) in membranes isolated from Bacillus subtilis 168 wild type and 11 strains bearing conditional lethal thermosensitive mutations in tagB, tagD, or tagF revealed that CGPTase deficiency was associated only with mutant tagF alleles. In vitro, thermosensitivity of CGPTase strongly suggests that the structural gene for this enzyme is tagF. We discuss apparent discrepancies between biochemical evidence favoring a membrane location for TagF and a previous report that suggested a cytoplasmic location based on sequence analysis.

Bacillus subtilis↗