scholarly journals De novo alanine synthesis in isolated oxygen-deprived rabbit myocardium.

1977 ◽  
Vol 252 (14) ◽  
pp. 5010-5018
Author(s):  
H Taegtmeyer ◽  
M B Peterson ◽  
V V Ragavan ◽  
A G Ferguson ◽  
M Lesch
Keyword(s):  
De Novo ◽  
Rabbit Myocardium ◽  
Alanine Synthesis

scholarly journals De novoβ-alanine synthesis in α-proteobacteria involves a β-alanine synthase from the uracil degradation pathway

2019 ◽  
Author(s):  
Mariana López-Sámano ◽  
Luis Fernando Lozano-Aguirre Beltrán ◽  
Rosina Sánchez-Thomas ◽  
Araceli Dávalos ◽  
Tomás Villaseñor ◽  
...  
Keyword(s):  
De Novo ◽  
Enzymatic Reaction ◽  
Pantothenic Acid ◽  
Acid Synthesis ◽  
Degradation Pathway ◽  
Partial Conservation ◽  
Alanine Synthesis ◽  
Pyrimidine Degradation ◽  
Cloned Gene

Abstractβ-alanine synthesis in bacteria occurs by the decarboxylation of L-aspartate as part of the pantothenate synthesis pathway. In the other two domains of life we find different pathways for β-alanine formation, such as sources from spermine in plants, uracil in yeast and by transamination reactions in insects and mammals. There are also promiscuous decarboxylases that can decarboxylate aspartate. Several bioinformatics studies about the conservation of pantothenate synthesis pathway performed on bacteria, archaea and eukaryotes, have shown a partial conservation of the pathway. As a part of our work, we performed an analysis of the prevalence of reported β-alanine synthesis pathways in 204 genomes of alpha-proteobacteria, with a focus on theRhizobialesorder. The aim of this work was to determine the enzyme or pathway used to synthetize β-alanine inRhizobium etliCFN42. Our bioinformatics analysis showed that this strain encodes the pyrimidine degradation pathway in its genome. We obtained a β-alanine synthase (amaB)mutant that was a β-alanine auxotroph. Complementation with the cloned gene restored the wild type phenotype. Biochemical analysis confirmed that the recombinant AmaB catalyzed the formation of β-alanine from 3-Ureidopropionic acidin vitro. Here we show a different way in bacteria to produce this essential metabolite.ImportanceSince the pioneer studies of Cronan (1980) on β-alanine synthesis inE. coli, it has been assumed that the decarboxilation of aspartate by the L-aspartate-α-decarboxylase it’s the main enzymatic reaction for β-alanine synthesis in bacteria. Forty years later, while we were studying the pantothenic acid synthesis in rhizobia, we demonstrate that a numerous and diverse group of bacteria classified as α-proteobacteria synthesize β-alaninede novousing β-alanine synthase, the last enzyme from the reductive pathway for uracil degradation.Additionally, there is a growing interest in β-amino acid due to its remarkable pharmaceuticals properties as hypoglycemic, antiketogenic and anti-fungal agents.

Synthesis, transfer, and phosphorylation of phosphoinositides in cardiac membranes

1990 ◽  
Vol 259 (6) ◽  
pp. C987-C994 ◽  
Author(s):  
R. A. Wolf
Keyword(s):  
Sarcoplasmic Reticulum ◽  
De Novo ◽  
De Novo Synthesis ◽  
Transfer Protein ◽  
Cardiac Membranes ◽  
Rabbit Myocardium ◽  
Phosphatidylinositol 4 ◽  
Junctional Sarcoplasmic Reticulum

Compartmentation of phosphoinositide synthesis and transfer of endogenous phosphatidylinositol (PI) were characterized in membrane fractions prepared from rabbit myocardium. De novo synthesis of PI was highly enriched in free sarcoplasmic reticulum (551 pmol.mg-1. min-1) compared with that in sarcolemma (26.8 pmol.mg-1. min-1) and junctional sarcoplasmic reticulum (178 pmol.mg-1. min-1). In contrast, PI phosphorylation was highly enriched in sarcolemma (2.69 nmol.mg-1.min-1) compared with that in free sarcoplasmic reticulum (0.22 nmol.mg-1.min-1) and junctional sarcoplasmic reticulum (0.38 nmol.mg-1.min-1). Phosphorylation of endogenous phosphatidylinositol 4-phosphate to phosphatidylinositol 4,5-bisphosphate was also enriched in sarcolemma (38.5 pmol.mg-1.min-1) compared with that in free sarcoplasmic reticulum (less than 5.0 pmol.mg-1.min-1) and junctional sarcoplasmic reticulum (6.5 pmol.mg-1.min-1). Transfer of endogenous PI was characterized as a mechanism to overcome compartmentation of PI synthesis in cardiac membranes. A 29-kDa PI transfer protein was purified 1,500-fold from cytosol of rabbit myocardium. Both cytosol and purified PI transfer protein catalyzed the transfer of endogenous PI from microsomal sites of synthesis to sarcolemma. In conclusion, synthesis of PI is highly enriched in free sarcoplasmic reticulum, whereas phosphorylation of phosphoinositides is highly enriched in sarcolemma. A 29-kDa PI transfer protein in myocardial cytosol can mediate in vitro transfer of de novo-synthesized PI to the sarcolemma.

scholarly journals The role of phosphoenolpyruvate carboxykinase in muscle alanine synthesis

1984 ◽  
Vol 224 (3) ◽  
pp. 971-976 ◽  
Author(s):  
T N Palmer ◽  
M A Caldecourt ◽  
J P Warner ◽  
M C Sugden
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
De Novo ◽  
Tricarboxylic Acid Cycle ◽  
Specific Inhibitor ◽  
Glycolytic Flux ◽  
Metabolic Role ◽  
14Co2 Production ◽  
Alanine Synthesis ◽  
Pep Carboxykinase

3-Mercaptopicolinic acid (3-MPA) is reportedly a specific inhibitor of phosphoenolpyruvate (PEP) carboxykinase and has hitherto been used accordingly to elucidate the metabolic role of PEP carboxykinase in vitro and in vivo. We show that 3-MPA has multiple effects on intermediary metabolism in hemidiaphragms from 40 h-starved rats. It decreases the release of lactate + pyruvate and alanine in hemidiaphragms provided with no added substrate or with valine, leucine or isoleucine. Moreover, irrespective of the substrate provided (none, valine, leucine, isoleucine, glucose, acetate, oleate), 3-MPA decreases the [lactate]/[pyruvate] ratio. 3-MPA is without effect on 14CO2 production from [U-14C]valine, [1-14C]valine, [1-14C]leucine, [U-14C]isoleucine or [1-14C]oleate, but stimulates 14CO2 production from [U-14C]glucose and [1-14C]pyruvate and inhibits 14CO2 production from [1-14C]acetate. Glycolytic flux (measured as 3H2O formation from [5-3H]glucose) is stimulated by 3-MPA. It is concluded that 3-MPA has site(s) of actions other than PEP carboxykinase and that the putative role of PEP carboxykinase in alanine synthesis de novo in skeletal muscle from tricarboxylic acid-cycle intermediates and related amino acids requires reappraisal.

scholarly journals De Novo Alanine Synthesis by Bacteroids of Mesorhizobium loti Is Not Required for Nitrogen Transfer in the Determinate Nodules of Lotus corniculatus

2005 ◽  
Vol 187 (15) ◽  
pp. 5493-5495 ◽  
Author(s):  
Shalini Kumar ◽  
Alexandre Bourdès ◽  
Philip Poole
Keyword(s):  
Enzyme Activity ◽  
De Novo ◽  
Lotus Corniculatus ◽  
Nitrogen Transfer ◽  
Mesorhizobium Loti ◽  
Alanine Dehydrogenase ◽  
Alanine Synthesis ◽  
Secretion Product ◽  
Cultured Bacteria ◽  
Nitrogen Secretion

ABSTRACT Deletion of both alanine dehydrogenase genes (aldA) in Mesorhizobium loti resulted in the loss of AldA enzyme activity from cultured bacteria and bacteroids but had no effect on the symbiotic performance of Lotus corniculatus plants. Thus, neither indeterminate pea nodules nor determinate L. corniculatus nodules export alanine as the sole nitrogen secretion product.

scholarly journals Despite similar rates of alanine release, fasting and diabetes affect de novo alanine synthesis differently

Diabetologia ◽  
1998 ◽  
Vol 41 (5) ◽  
pp. 606-607 ◽  
Author(s):  
D. Meynial-Denis ◽  
L. Foucat ◽  
M. Mignon ◽  
A. Chavaroux ◽  
J. Prugnaud ◽  
...  
Keyword(s):  
De Novo ◽  
Alanine Synthesis

scholarly journals Regulation of l-Alanine Dehydrogenase in Rhizobium leguminosarum bv. viciae and Its Role in Pea Nodules

2004 ◽  
Vol 186 (3) ◽  
pp. 842-849 ◽  
Author(s):  
Emma Lodwig ◽  
Shalini Kumar ◽  
David Allaway ◽  
Alex Bourdes ◽  
Jürgen Prell ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
De Novo ◽  
Dry Weight ◽  
Northern Blotting ◽  
Alanine Dehydrogenase ◽  
Living Culture ◽  
Optimal Functioning ◽  
Alanine Synthesis ◽  
Sole Product

ABSTRACT Alanine dehydrogenase (AldA) is the principal enzyme with which pea bacteroids synthesize alanine de novo. In free-living culture, AldA activity is induced by carboxylic acids (succinate, malate, and pyruvate), although the best inducer is alanine. Measurement of the intracellular concentration of alanine showed that AldA contributes to net alanine synthesis in laboratory cultures. Divergently transcribed from aldA is an AsnC type regulator, aldR. Mutation of aldR prevents induction of AldA activity. Plasmid-borne gusA fusions showed that aldR is required for transcription of both aldA and aldR; hence, AldR is autoregulatory. However, plasmid fusions containing the aldA-aldR intergenic region could apparently titrate out AldR, sometimes resulting in a complete loss of AldA enzyme activity. Therefore, integrated aldR::gusA and aldA::gusA fusions, as well as Northern blotting, were used to confirm the induction of aldA activity. Both aldA and aldR were expressed in the II/III interzone and zone III of pea nodules. Overexpression of aldA in bacteroids did not alter the ability of pea plants to fix nitrogen, as measured by acetylene reduction, but caused a large reduction in the size and dry weight of plants. This suggests that overexpression of aldA impairs the ability of bacteroids to donate fixed nitrogen that the plant can productively assimilate. We propose that the role of AldA may be to balance the alanine level for optimal functioning of bacteroid metabolism rather than to synthesize alanine as the sole product of N2 reduction.

De novo synthesis of alanine by the perfused rat hindlimb

1976 ◽  
Vol 230 (5) ◽  
pp. 1379-1384 ◽  
Author(s):  
B Grubb
Keyword(s):  
Glucose Uptake ◽  
Glucose Concentration ◽  
De Novo ◽  
Glucose Measurement ◽  
De Novo Synthesis ◽  
Bicarbonate Buffer ◽  
Large Production ◽  
Alanine Synthesis ◽  
Alanine Production ◽  
Isolated Rat

Due to the disproportionately large production of alanine by muscle, it has been suggested that part of the alanine released by muscle is synthesized de novo by the transamination of glucose-derived pyruvate. This glucose-alanine conversion was quantitated in the isolated rat hindlimb perfused with a solution of bicarbonate buffer containing 2% albumin, 2.4% dextran, 2.5-15.9 mM glucose, 32-34% dog erythrocytes, and 0.05 muCi/ml [14C]glucose. Measurement of labeled alanine production allowed quantitation of de novo alanine synthesis. De novo derived alanine accounted for an average of 33% of the total alanine released by the perfused tissue (perfusate glucose concentration 8.3 mM), concurrently 2.7% of the glucose taken up by the limb was converted to alanine. By increasing the glucose concentration perfusing the muscle, both the rate of glucose uptake and de novo alanine release were increased. Addition of insulin to the perfusate (700 muU/ml) resulted in a significant increase in the rate of glucose uptake and de novo alanine production, but the rate of total alanine release was significantly decreased by the hormone. It was concluded that de novo alanine production accounts for a sizeable portion of the total alanine released by muscle, nevertheless a comparatively small fraction of the glucose carbons are actually transformed to alanine.

Plasma amino acid kinetics during acute states of glucagon deficiency and excess in healthy adults

1990 ◽  
Vol 258 (1) ◽  
pp. E78-E85 ◽  
Author(s):  
C. Couet ◽  
N. K. Fukagawa ◽  
D. E. Matthews ◽  
D. M. Bier ◽  
V. R. Young
Keyword(s):  
Amino Acid ◽  
De Novo ◽  
Healthy Young Adult ◽  
Peripheral Tissues ◽  
Adult Men ◽  
Branched Chain Amino Acid ◽  
Alanine Synthesis ◽  
Plasma Hormone ◽  
Branched Chain ◽  
Plasma Leucine

The effects of glucagon deficiency and excess on plasma leucine, lysine, and alanine were examined in six healthy young adult men, with primed continuous infusions of L-[1-13C]- or L-[5,5,5-2H3]leucine, L-[alpha-15N]-lysine, and L-[3-13C]alanine for 150 min before and during 210 min of either a glucagon-deficient euglycemic state (experiment 1), a basal glucagon state (experiment 2), or a glucagon-excess state (experiment 3). Steady-state plasma hormone levels were achieved by infusion of somatostatin (250 micrograms/h) and insulin (0.07 mU.kg-1.min-1), without (experiment 1) or with an infusion of glucagon at 0.7 ng.kg-1.min-1 (experiment 2) or 2.5 ng.kg-1.min-1 (experiment 3). Plasma branched-chain amino acid (AA) concentrations did not change with altered glucagon status, whereas significant differences were observed for plasma lysine, alanine, glycine, serine, threonine, proline, tyrosine, citrulline, and ornithine levels (0.05 greater than P greater than 0.001). Plasma leucine, lysine, and alanine fluxes and the rate of de novo alanine synthesis showed no significant changes with either glucagon deficiency or excess. These findings lead to the conclusion that glucagon-induced alterations in plasma AA profiles are not due to changes in the rate of appearance of AA from peripheral tissues but rather a consequence of changes in the fate of AA within the splanchnic region.

The Morphology of the Rat Kidney Following Folic Acid Administration

1970 ◽  
Vol 28 ◽  
pp. 200-201
Author(s):  
Aline Byrnes ◽  
Elsa E. Ramos ◽  
Minoru Suzuki ◽  
E.D. Mayfield
Keyword(s):  
Folic Acid ◽  
De Novo ◽  
Specific Activity ◽  
Rat Kidney ◽  
Present Report ◽  
Intracellular Localization ◽  
Male Rats ◽  
Renal Hypertrophy ◽  
Electron Microscopic ◽  
Biochemical Alterations

Renal hypertrophy was induced in 100 g male rats by the injection of 250 mg folic acid (FA) dissolved in 0.3 M NaHCO3/kg body weight (i.v.). Preliminary studies of the biochemical alterations in ribonucleic acid (RNA) metabolism of the renal tissue have been reported recently (1). They are: RNA content and concentration, orotic acid-c14 incorporation into RNA and acid soluble nucleotide pool, intracellular localization of the newly synthesized RNA, and the specific activity of enzymes of the de novo pyrimidine biosynthesis pathway. The present report describes the light and electron microscopic observations in these animals. For light microscopy, kidney slices were fixed in formalin, embedded, sectioned, and stained with H & E and PAS.

Sign in / Sign up

Export Citation Format

Share Document