Glycerol vic-cyclic phosphate in rat tissues.
Ontology highlight
ABSTRACT:
SUBMITTER: Clarke NG
PROVIDER: S-EPMC1162516 | biostudies-other | 1980 Apr
REPOSITORIES: biostudies-other
Similar Datasets
Project description:1. A soluble phosphodiesterase is present in mammalian tissues which rapidly hydrolyses enantiomorphs of rac-glycerol 1:2-cyclic phosphate, producing rac-glycerol 1-phosphate. 2. The enzyme has been purified up to 1700-fold by a combination of acetone precipitation and chromatography on DEAE-Sephadex A-50, Sephadex G-150 and hydroxyapatite. 3. The Km with glycerol cyclic phosphate as substrate is 7.2 mM, and the pH optimum broad (6.9--7.5). The molecular weight (by gel filtration) of the enzyme is approx. 35500. 4. The phosphodiesterase has no requirement for Ca2+ or Mg2+, but is stimulated by reducing agents (cysteine, dithiothreitol) and Fe2+. 5. The purified phosphodiesterase preparation also hydrolysed 3':5'-cyclic AMP, producing 5'-AMP exclusively, and 2':3'-cyclic AMP, forming 3'-AMP and 2'-AMP in the ratio 7:3. Bis-(p-nitrophenyl) phosphate was slowly hydrolysed, but other phosphodiesters tested were not attacked. 6. The phosphodiesterase is inhibited by theophylline and o-phenanthroline. It is inhibited by Pi and by a variety of phosphomonoesters, of which certain aromatic primary phosphates are particularly effective.
| S-EPMC1185812 | biostudies-other
Project description:Glycerol 1:2-cyclic phosphate is released simultaneously with glycerophosphate when kidney glycerophosphinicocholine diesterase (EC 3.1.4.2) acts on glycerylphosphorylcholine and glycerylphosphorylethanolamine. The percentage of cyclic phosphate ester formed is increased at pH values below the optimum and is decreased when Mg2+ or Ca2+ is added to stimulate the reaction.
| S-EPMC1172647 | biostudies-other
Project description:Rat adipose-tissue glycerol phosphate acyltransferase can be inactivated in a phosphorylation reaction catalysed by cyclic AMP-dependent protein kinase and reactivated by treatment with alkaline phosphatase. These results suggest that phosphorylation of glycerol phosphate acyltransferase may be involved in the hormonal control of esterification.
| S-EPMC1186273 | biostudies-other
Project description:Sequence analysis using the Promoser program predicted two promoter-like regions for rat mtGPAT: a distal promoter approximately 30kb upstream and a proximal promoter near the first translational codon. Rat liver cells transfected with pGL3-basic vector containing the distal and proximal promoter resulted in 10.8- and 4.8-fold increase in the luciferase activity, respectively. Results of electromobility shift assay and chromatin immunoprecipitation suggested binding of transcription factors to the distal and proximal promoter regions. 5' RACE PCR showed two transcripts with different transcriptional start sites. When transfected rat liver cells were starved and refed, there was about 2.7-fold increase in the luciferase activity with cells transfected with the distal promoter while the proximal promoter showed no change. Thus, the two promoters could be functionally distinguished. Taken together, the results suggest that there are two promoters for rat mtGPAT gene and that the transcriptional regulation is mediated through the distal promoter.
| S-EPMC2262852 | biostudies-literature
Project description:Thyroid hormone (T3)-dependent gene expression of the adenine nucleotide translocase (ANT) and the FAD-linked glycerol 3-phosphate dehydrogenase (mGPDH) was investigated in several rat tissues. Both proteins provide an important link between cytosolic and mitochondrial metabolic pathways and seem to be involved in the stimulation of mitochondrial oxygen consumption in response to T3. Here we show that two ANT isoforms are expressed in rat, the muscle-specific ANT1 form and the ubiquitous ANT2 form. The expression of ANT1 mRNA is not sensitive to T3 whereas the amount of ANT2 mRNA is increased 7-9-fold in liver and heart within 12-48 h after T3 application. Little or no effect of T3 on ANT2 mRNA was observed in kidney and brain. The mRNA changes are paralleled by an increase in ANT protein, thus explaining the accelerated ADP/ATP exchange observed in mitochondria isolated from hyperthyroid rats. The key role of ANT2 in the control of hyperthyroid metabolism is evident because the expression of the mersalyl-sensitive phosphate carrier and the mitochondrial creatine kinase mRNA, which are functionally linked to ANT, did not respond to T3. Similarly to the ADP/ATP exchange, the transfer of cytosolic NADH to the respiratory chain via the glycerophosphate shuttle is very sensitive to T3. Recently we demonstrated the 10-15-fold induction of mGPDH mRNA in rat liver after administration of T3 [Müller and Seitz (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 10581-10585]. Here we show that, in contrast with ANT2, the time course of induction is fast (4-6 h). Furthermore, mGPDH mRNA is induced 6-fold by T3 in heart and 4-fold in kidney. From these results we conclude that the T3-mediated transcriptional induction leading to increased activity of ANT2 and mGPDH contributes considerably to the increase in mitochondrial oxygen consumption in rat tissues.
| S-EPMC1217572 | biostudies-other
Project description:Glycerol is a byproduct of biodiesel production and is generated in large amounts, which has resulted in an increased interest in its valorization. In addition to its use as an energy source directly, the chemical modification of glycerol may result in value-added derivatives. Herein, acid phosphatases employed in the synthetic mode were evaluated for the enzymatic phosphorylation of glycerol. Nonspecific acid phosphatases could tolerate glycerol concentrations up to 80 wt % and pyrophosphate concentrations up to 20 wt % and led to product titers up to 167 g L-1 in a kinetic approach. In the complementary thermodynamic approach, phytases were able to condense glycerol and inorganic monophosphate directly. This unexpected behavior enabled the simple and cost-effective production of rac-glycerol-1-phosphate from crude glycerol obtained from a biodiesel plant. A preparative-scale synthesis on a 100 mL-scale resulted in the production of 16.6 g of rac-glycerol-1-phosphate with a reasonable purity (≈75 %).
| S-EPMC7187357 | biostudies-literature
Project description:The activities of glycerol 3-phosphate dehydrogenase (EC 1.1.1.8), glycerol kinase (EC 2.7.1.30), lactate dehydrogenase (EC 1.1.1.27), "malic' enzyme (L-malate-NADP+ oxidoreductase; EC 1.1.1.40) and the beta-oxoacyl-(acyl-carrier protein) reductase component of the fatty acid synthetase complex were measured in nine hepatoma lines (8 in rats, 1 in mouse) and in the livers of host animals. With the single exception of Morris hepatoma 16, which had unusually high glycerol 3-phosphate dehydrogenase activity, the activities of glycerol 3-phosphate dehydrogenase and glycerol kinase were highly correlated in normal livers and hepatomas (r = 0.97; P less than 0.01). The activities of these two enzymes were not strongly correlated with the activities of any of the other three enzymes. The primary function of hepatic glycerol 3-phosphate dehydrogenase appears to be in gluconeogenesis from glycerol.
| S-EPMC1165575 | biostudies-other
Project description:Protein allosteric pathways are investigated in the imidazole glycerol phosphate synthase heterodimer in an effort to elucidate how the effector (PRFAR, N'-[(5'-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide) activates glutaminase catalysis at a distance of 25 ? from the glutamine-binding site. We apply solution NMR techniques and community analysis of dynamical networks, based on mutual information of correlated protein motions in the active and inactive enzymes. We find evidence that the allosteric pathways in the PRFAR bound enzyme involve conserved residues that correlate motion of the PRFAR binding loop to motion at the protein-protein interface, and ultimately at the glutaminase active site. The imidazole glycerol phosphate synthase bienzyme is an important branch point for the histidine and nucleotide biosynthetic pathways and represents a potential therapeutic target against microbes. The proposed allosteric mechanism and the underlying allosteric pathways provide fundamental insights for the design of new allosteric drugs and/or alternative herbicides.
| S-EPMC3365145 | biostudies-literature
Project description:Incubation of rat adipose-tissue microsomal fractions with iodoacetate caused an inactivation of glycerol phosphate acyltransferase that could be prevented by the presence of palmitoyl-CoA. A microsomal protein of subunit Mr 54 000 was found to react with radioactively labelled iodoacetate in the absence, but not in the presence, of palmitoyl-CoA. It is suggested that this protein is a component of glycerol phosphate acyltransferase. Incubation of rat adipose-tissue microsomal fractions with the catalytic subunit of cyclic AMP-dependent protein kinase, ATP and Mg2+ caused an inactivation of glycerol phosphate acyltransferase whose magnitude depended on the conditions used for assay of the acyltransferase. Rat adipose tissue microsomal proteins were phosphorylated by using protein kinase and [gamma-32P]ATP. One of the phosphorylated proteins was very similar, but not identical, in mobility to the Mr-54 000 protein labelled by iodoacetate. In contrast with a previous report [Sooranna & Saggerson (1976) FEBS Lett. 64, 36-39], no changes could be detected in the activity of glycerol phosphate acyltransferase in adipocytes treated with adrenaline. Adipocytes were labelled with [32P]Pi and treated with adrenaline, but no 32P was incorporated into the Mr-54000 protein labelled by iodoacetate. The results suggest that the activity of adipose-tissue microsomal glycerol phosphate acyltransferase is not directly controlled by phosphorylation.
| S-EPMC1144402 | biostudies-other
Project description:Major facilitators represent the largest superfamily of secondary active transporter proteins and catalyze the transport of an enormous variety of small solute molecules across biological membranes. However, individual superfamily members, although they may be architecturally similar, exhibit strict specificity toward the substrates they transport. The structural basis of this specificity is poorly understood. A member of the major facilitator superfamily is the glycerol-3-phosphate (G3P) transporter (GlpT) from the Escherichia coli inner membrane. GlpT is an antiporter that transports G3P into the cell in exchange for inorganic phosphate (P(i)). By combining large-scale molecular-dynamics simulations, mutagenesis, substrate-binding affinity, and transport activity assays on GlpT, we were able to identify key amino acid residues that confer substrate specificity upon this protein. Our studies suggest that only a few amino acid residues that line the transporter lumen act as specificity determinants. Whereas R45, K80, H165, and, to a lesser extent Y38, Y42, and Y76 contribute to recognition of both free P(i) and the phosphate moiety of G3P, the residues N162, Y266, and Y393 function in recognition of only the glycerol moiety of G3P. It is the latter interactions that give the transporter a higher affinity to G3P over P(i).
| S-EPMC2749764 | biostudies-literature