Increase In Amino Acid Content Research Articles

Fructan, sucrose and related enzyme activities are preserved in timothy (Phleum pratenseL.) during wilting

AbstractTimothy (Phleum pratenseL.) is an important forage grass used for pasture, hay and silage in regions with cool and humid growth seasons. Harvesting conditions could reduce its nutritive value, particularly with extended wilting periods. To understand how daytime or night‐time wilting influences the nutritive value of timothy, this study investigated the metabolism of non‐structural carbohydrates, including fructan and starch, together with total soluble protein and amino acid patterns in timothy plants harvested at two maturity stages (heading and anthesis) and wilted under controlled conditions for 24 h at two temperatures (15°C, 20°C) and two light regimes (darkness, light) by simulating different wilting management practices. Correlation analysis with the whole dataset showed that soluble protein, glucose and starch contents declined in plant tissues concomitantly with water loss, while amino acid, sucrose and fructose contents increased. Transient increase in amino acid content suggests that the decrease in protein content was due to proteolysis during wilting. Sucrose and fructose contents generally increased in plant tissues harvested at anthesis and wilted in light whereas they were unaffected in plants wilted in darkness. Fructan content remained stable. Fructan exohydrolase (FEH) and soluble acid invertase (INV) activities were well preserved during the first 12 h of wilting and might facilitate the fermentation process at the beginning of ensiling by supplying fructose from fructans and hexoses from sucrose to the fermentive bacteria.

Effects of fertilisation on amino acid mobilisation by a plant‐manipulating insect

1. Phytophagous insects frequently manipulate their host‐plant to improve their immediate environment. This generally implies substantial modifications of host metabolism, and sometimes an alteration of nitrogen allocation within the host‐plant. However, the outcome of plant manipulation on amino acid or protein content can be modulated by environmental factors and host‐plant traits.2. It was investigated whether the pseudogall induced by the aphid Phloeomyzus passerinii (Signoret) (Aphididae: Phloeomyzinae) in the bark of its host‐plant affects the amino acid content in bark tissues, and whether the strength of the modification is modulated by the fertilisation regime and/or the resistance level of the host‐plant. The development of aphid colonies on a resistant and a susceptible poplar genotype, under three fertilisation regimes, was studied. After the development of colonies, the free and protein‐bound amino acid content of the infested bark were quantified.3. Fertilisation enhanced poplar growth and increased the free amino acid content of bark tissues. Infestation also triggered accumulations of both free and protein‐bound amino acids in the feeding sites, but in the susceptible genotype only. The increase in amino acid content was more pronounced when fertilisation was low, and fertilisation did not enhance aphid development.4. In conclusion, infestation by P. passerinii triggers an accumulation of amino acids, but the effect is influenced by both the fertilisation regime and the resistance level of the host‐plant. This suggests that P. passerinii could affect the allocation of nutrients within trees during outbreaks.

Complementary transcriptomic and proteomic analyses of a chlorophyll-deficient tea plant cultivar reveal multiple metabolic pathway changes

To uncover the mechanisms that underlie the chlorina phenotype of the tea plant, this study employs morphological, biochemical, transcriptomic, and iTRAQ-based proteomic analyses to compare the green tea cultivar LJ43 and the yellow-leaf tea cultivar ZH1. ZH1 exhibited the chlorina phenotype, with significantly decreased chlorophyll content and abnormal chloroplast development compared with LJ43. ZH1 also displayed higher theanine and free amino acid content and lower carotenoid and catechin content. Microarray and iTRAQ analyses indicated that the differentially expressed genes and proteins could be mapped to the following pathways: 'phenylpropanoid biosynthesis,' 'glutathione metabolism,' 'phenylalanine metabolism,' 'photosynthesis,' and 'flavonoid biosynthesis.' Altered gene and protein levels in these pathways may account for the increased amino acid content and reduced chlorophyll and flavonoid content of ZH1. Altogether, this study combines transcriptomic and proteomic approaches to better understand the mechanisms responsible for the chlorina phenotype.

Impact of fermentation on nitrogenous compounds of cocoa beans (Theobroma cacao L.) from various origins

Tangential filtration technique was used to separate and quantify three different fractions of nitrogenous compounds depending on their molecular size, during cocoa fermentation. On every phenotype and origin analyzed, protein profile of non-fermented samples was similar. During fermentation course, proteins get degraded with a concomitant increase in amino acids content. Peptides between 3 and 10kDa were observed at low levels. A strong correlation between amino acids and ammonia nitrogen, a fermentation marker was found. Attention was drawn on each fraction, and enabled to point out other phenomenon occurring during fermentation. The migration of some nitrogenous compounds towards the bean shell during fermentation was demonstrated. Acetone treatment of cocoa powder prior to SDS–PAGE led to losses of nitrogenous compounds. This result gives clues on the tanning phenomenon carried out by polyphenols on nitrogenous compounds, phenomenon which increases during fermentation.

Phosphatidylinositol 3-kinase signaling determines kidney size.

Kidney size adaptively increases as mammals grow and in response to the loss of 1 kidney. It is not clear how kidneys size themselves or if the processes that adapt kidney mass to lean body mass also mediate renal hypertrophy following unilateral nephrectomy (UNX). Here, we demonstrated that mice harboring a proximal tubule-specific deletion of Pten (Pten(ptKO)) have greatly enlarged kidneys as the result of persistent activation of the class I PI3K/mTORC2/AKT pathway and an increase of the antiproliferative signals p21(Cip1/WAF) and p27(Kip1). Administration of rapamycin to Pten(ptKO) mice diminished hypertrophy. Proximal tubule-specific deletion of Egfr in Pten(ptKO) mice also attenuated class I PI3K/mTORC2/AKT signaling and reduced the size of enlarged kidneys. In Pten(ptKO) mice, UNX further increased mTORC1 activation and hypertrophy in the remaining kidney; however, mTORC2-dependent AKT phosphorylation did not increase further in the remaining kidney of Pten(ptKO) mice, nor was it induced in the remaining kidney of WT mice. After UNX, renal blood flow and amino acid delivery to the remaining kidney rose abruptly, followed by increased amino acid content and activation of a class III PI3K/mTORC1/S6K1 pathway. Thus, our findings demonstrate context-dependent roles for EGFR-modulated class I PI3K/mTORC2/AKT signaling in the normal adaptation of kidney size and PTEN-independent, nutrient-dependent class III PI3K/mTORC1/S6K1 signaling in the compensatory enlargement of the remaining kidney following UNX.

Evidence of Salicylic Acid-Mediated Protein Degradation and Amino Acid Transport in Mature Leaves of Brassica napus

Brassica napus is characterized by low nitrogen remobilization efficiency from source leaves to seed filling, which is mainly due to poor hydrolysis of foliar proteins. To investigate the roles of salicylic acid (SA) in the proteolytic process in source organ at the early pod-filling stage, the SA concentration, protein profile, protease activity, and amino acid transporter genes were measured in mature leaves sprayed with SA or control at four and 30 days after treatment. Exogenous SA application resulted in an increase in SA concentration, accompanied with a significant decrease in protein with concomitant increase in amino acid concentration. Rubisco proteins were largely degraded in the SA-applied leaves. A significant increase in protease activity (up to 98 % at day 30) in the SA-applied leaves was observed. The increased proteolytic activity was confirmed in-gel staining of protease. Three amino acid permeases, BnAAP1, BnAAP2, and BnAAP6, were identified in mature leaves. Exogenous SA application enhanced the expression of three amino acid transporter genes. The present study clearly indicates that the SA level increased by exogenous SA application could improve N remobilization efficiency by up-regulating protein degradation and amino acid transport in source leaves at the pod-filling stage.

Hepatic and fecal metabolomic analysis of the effects of Lactobacillus rhamnosus GG on alcoholic fatty liver disease in mice.

The interactions among the gut, liver, and immune system play an important role in liver disease. Probiotics have been used for the treatment and prevention of many pathological conditions, including liver diseases. Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS) was used herein, in conjunction with chemometric data analysis, to identify metabolites significantly affected by probiotics in mice fed with or without alcohol. The metabolomics analysis indicates that the levels of fatty acids increased in mouse liver and decreased in mouse feces when mice were chronically exposed to alcohol. Supplementing the alcohol-fed mice with culture supernatant from Lactobacillus rhamnosus GG (LGGs) normalized these alcohol-induced abnormalities and prevented alcoholic liver disease (ALD). These results agree well with previous studies. In addition to diet-derived long chain fatty acids (LCFAs), LGGs may positively modify the gut's bacterial population to stimulate LCFA synthesis, which has been shown to enhance intestinal barrier function, reduce endotoxemia, and prevent ALD. We also found that several amino acids, including l-isoleucine, a branched chain amino acid, were downregulated in the liver and fecal samples from animals exposed to alcohol and that the levels of these amino acids were corrected by LGGs. These results demonstrate that LGGs alleviates alcohol-induced fatty liver by mechanisms involving increasing intestinal and decreasing hepatic fatty acids and increasing amino acid concentration.

BI-10 * pH-WEIGHTED MRI IN HUMAN GLIOMAS

Regions of proliferating tumor are characterized by extracellular acidosis and hypoxia. Additionally, tumor cells utilize glutamine and other amino acids for fuel, resulting in elevated extracellular concentrations of glutamine in areas of metabolically active tumor. In the current study we explore the use of chemical exchange saturation transfer (CEST) MRI targeting exchangeable protons on the amine functional group in free amino acids as a pH-weighted imaging biomarker for non-invasively identifying regions of low pH, suggestive of regions with active tumor. The dependence of CEST contrast on pH was measured for three amino acids, and the dependence of CEST contrast on metabolite concentration was measured for glutamine. CEST data was collected in a cohort of twelve GBM patients undergoing radiochemotherapy. CEST data and corresponding histology were collected in a patient with suspected low grade glioma and a GBM patient at tumor recurrence. Results show a sigmoidal relationship between CEST contrast and pH within a range of 5.0-8.0. CEST contrast increased with both decreasing pH and increasing amino acid concentration, and the three amino acids produced similar CEST signatures within a physiologically relevant range of pH (6.0-7.0). Clinically, some patients who showed elevated CEST contrast in the tumor region appeared to show an increase in tumor volume at six months post-treatment, while a patient who did not show elevated CEST contrast in the tumor region appeared to show a slight decrease in tumor volume at six months post-treatment. In biopsy patients, regions of CEST contrast suggestive of low pH and active tumor correctly identified proliferative tumor, while areas suggestive of normal pH showed gliosis. In summary, results suggest CEST imaging of the amine functional group on free amino acids is sensitive to acidic pH and elevated amino acid concentration, allowing non-invasive identification of metabolically active tumor with a high specificity.

The leaching and adsorption of gold using low concentration amino acids and hydrogen peroxide: Effect of catalytic ions, sulphide minerals and amino acid type

The leaching of gold using alkaline amino acids–hydrogen peroxide solutions at low concentrations has been studied. The application of alkaline amino acid–hydrogen peroxide system may offer an alternative and environmentally benign process for gold leaching, particularly in the context of leaching low grade gold ores in an in-situ or in heap leach processes. In the presence of an oxidant or oxidants, it was found that amino acids can dissolve gold at alkaline condition at low and moderate temperature. Heating the leach solution between 40 and 60°C was found to enhance the gold dissolution significantly in alkaline amino acid–peroxide solutions. It was also found that gold dissolution increases by increasing amino acid concentration, peroxide and pH. Amino acids acts synergistically to dissolve gold. Although glycine showed the highest gold dissolution as a single amino acid compared to histidine and alanine, histidine was found to enhance gold dissolution when used in equimolar amounts with glycine. The presence of Cu2+ ion enhances gold dissolution in the glycine–peroxide solutions. The process will propose an environmentally benign process for gold treatment in order to replace the use of cyanide in heap or in-situ leaching. In the presence of pyrite, the amount of gold leached was lower due to the peroxide consumption in sulphide oxidation.

Endolysosomal Membrane Trafficking Complexes Drive Nutrient-Dependent TORC1 Signaling to Control Cell Growth in Saccharomyces cerevisiae

The rapamycin-sensitive and endomembrane-associated TORC1 pathway controls cell growth in response to nutrients in eukaryotes. Mutations in class C Vps (Vps-C) complexes are synthetically lethal with tor1 mutations and confer rapamycin hypersensitivity in Saccharomyces cerevisiae, suggesting a role for these complexes in TORC1 signaling. Vps-C complexes are required for vesicular trafficking and fusion and comprise four distinct complexes: HOPS and CORVET and their minor intermediaries (i)-CORVET and i-HOPS. We show that at least one Vps-C complex is required to promote TORC1 activity, with the HOPS complex having the greatest input. The vps-c mutants fail to recover from rapamycin-induced growth arrest and show low levels of TORC1 activity. TORC1 promotes cell growth via Sch9, a p70(S6) kinase ortholog. Constitutively active SCH9 or hyperactive TOR1 alleles restored rapamycin recovery and TORC1 activity of vps-c mutants, supporting a role for the Vps-C complexes upstream of TORC1. The EGO GTPase complex Exit from G0 Complex (EGOC) and its homologous Rag-GTPase complex convey amino acid signals to TORC1 in yeast and mammals, respectively. Expression of the activated EGOC GTPase subunits Gtr1(GTP) and Gtr2(GDP) partially suppressed vps-c mutant rapamycin recovery defects, and this suppression was enhanced by increased amino acid concentrations. Moreover, vps-c mutations disrupted EGOC-TORC1 interactions. TORC1 defects were more severe for vps-c mutants than those observed in EGOC mutants. Taken together, our results support a model in which distinct endolysosomal trafficking Vps-C complexes promote rapamycin-sensitive TORC1 activity via multiple inputs, one of which involves maintenance of amino acid homeostasis that is sensed and transmitted to TORC1 via interactions with EGOC.

Whey protein-containing product reduces muscle damage induced by running in male adults

Whey protein has been reported to reduce exercise-induced muscle damage. Previous reports have focused mainly on post-exercise data, with results obtained before or during exercise being limited. This study examined the effect of consuming whey protein on muscle damage before, during (three times), and immediately after a 60-min running session. The study was designed as a placebo-controlled, two-period cross-over trial. Fourteen male adults were enrolled in the study and completed a 60-min running session at an intensity >70 % of maximal oxygen uptake ( $$\dot {\text{V}}\text {O}_{2\text{max}}$$ ). Once before, three times during, and once after this exercise the subjects consumed a serving of a test product that contained 22.8 g of whey protein as the main ingredient, or a similar placebo product made by removing only the whey protein. Blood samples were collected during the pre-exercise period to 24 h after the running session was completed. Compared to the placebo product, the test product significantly suppressed the elevation of serum creatine kinase (CK) and myoglobin after exercise (P < 0.05) and suppressed the elevation of plasma interleukin (IL)-6, but not significantly (P = 0.055). Plasma amino acid (AA) concentrations increased immediately after exercise following ingestion of the test product, and negative correlations (P < 0.05) were observed between AA and both serum CK and plasma IL-6 concentrations immediately after exercise. Whey protein consumption likely plays an important role in the increase of AA concentrations in the blood, even during exercise, and was associated with a decrease in exercise-related muscle damage and inflammation.

Influence of selected soil-climatic parameters and application method of tribenuron methyl on biomass productivity and amino acids content in weeds

Pot experiments were carried out in controlled environment chambers to investigate the influence of climatic factors and application methods on tribenuron methyl activity on three weed species: Anthemis arvensis, Galium aparine and Stellaria media. Tribenuron methyl was used at a dose of 15 g a.i. ha−1 solo or in mixture with a surfactant. Herbicide activity was subjected to the influence of environmental conditions such as: air temperature (25/16°C and 8/2°C day/night), relative humidity (75% and 50%) and soil moisture (60% and 30%). Herbicide efficacy was evaluated on fresh weight and reduction in free branched-chain amino acids content. The surfactant affected tribenuron methyl efficacy differently, depending on the environmental conditions and weed species susceptibility. Control of S. media did not require addition of a surfactant to achieve a high efficacy. The joint application enhanced herbicide efficacy against A. arvensis compared to solo application under low relative humidity (RH). Galium aparine was satisfactory controlled only when the surfactant was added to the spray solution, even under optimal environmental conditions. In most cases the amino acids content declined after exposure to tribenuron methyl and tank mix with the surfactant further improved its reduction. Increased amino acid content was observed in G. aparine and A. arvensis exposed to low soil moisture and G. aparine exposed to 50% RH, probably due to amino acids overproduction as a response to environmental conditions.

The Effect of Aspartic Acid and Glycine on Amorphous Calcium Carbonate (ACC) Structure, Stability and Crystallization

The effect of organic molecules on CaCO3 crystallization, in particular on the formation of the initial amorphous calcium carbonate (ACC) phase, is poorly understood despite this knowledge being crucial for designing biomimetic compounds with specific function, strength and stability. We monitored ACC crystallization in the presence of varying concentrations of aspartic acid (ASP) and glycine (GLY). We observed an increase in ACC lifetime with increasing amino acid concentrations and showed that the amino acid molecules sorbed onto the ACC particles. However, little if any difference in composition and atomic structure or the so formed ACC was observed. Similarly, the crystallization pathway of ACC via vaterite and calcite although delayed, was only slightly affected by the added amino acids. The only exemption was at the highest tested ASP concentration where ACC formation was inhibited, The calcite crystals that formed in the presence of ASP had rounded edges and rough surfaces, features that are not observed for the pure, inorganic calcite or calcite formed in the presence of GLY. Overall, the results suggest that the amino acids affected ACC lifetime through the inhibition of crystal nucleation and growth, more so in the presence of ASP than GLY.

Effect of temperature and additives on the critical micelle concentration and thermodynamics of micelle formation of sodium dodecyl benzene sulfonate and dodecyltrimethylammonium bromide in aqueous solution: A conductometric study

Specific conductance of (0.3 to 3.0)mmol·kg−1 sodium dodecyl benzene sulfonate (SDBS) and (3.0 to 30.0)mmol·kg−1 dodecyltrimethylammonium bromide (DTAB) has been determined in water and in the presence of (0.01, 0.05 and 0.10)mol·kg−1 aqueous solution of glutamine/histidine/methionine at T=(293.15, 298.15, 303.15, 308.15 and 313.15)K. From the conductivity data, the critical micellar concentration (CMC) and thermodynamic parameters of micellization (ΔGmo,ΔHmo and ΔSmo) have been computed by applying the mass action model. Enthalpy–entropy compensation effect has also been observed. The effect of amino acid on the micellar properties of SDBS and DTAB depends upon their nature, concentration, as well as on temperature and has been used to study the interactions present in the micellar systems. There occurs a gradual increase in the value of CMC with temperature in case of SDBS while in case of DTAB, it passes through a broad minimum and then tends to increase with increase in temperature. Increase of amino acid concentration is found to decrease CMC in both the surfactants. The ΔGmo values are negative and the feasibility of the micellization is found to increase with rise in temperature. The magnitude of hydrophilic and hydrophobic dehydration determines whether the CMC values increase or decrease with rise in temperature.

Pea aphid promotes amino acid metabolism both in Medicago truncatula and bacteriocytes to favor aphid population growth under elevated CO2

Rising atmospheric CO(2) levels can dilute the nitrogen (N) resource in plant tissue, which is disadvantageous to many herbivorous insects. Aphids appear to be an exception that warrants further study. The effects of elevated CO(2) (750 ppm vs. 390 ppm) were evaluated on N assimilation and transamination by two Medicago truncatula genotypes, a N-fixing-deficient mutant (dnf1) and its wild-type control (Jemalong), with and without pea aphid (Acyrthosiphon pisum) infestation. Elevated CO(2) increased population abundance and feeding efficiency of aphids fed on Jemalong, but reduced those on dnf1. Without aphid infestation, elevated CO(2) increased photosynthetic rate, chlorophyll content, nodule number, biomass, and pod number for Jemalong, but only increased pod number and chlorophyll content for dnf1. Furthermore, aphid infested Jemalong plants had enhanced activities of N assimilation-related enzymes (glutamine synthetase, Glutamate synthase) and transamination-related enzymes (glutamate oxalate transaminase, glutamine phenylpyruvate transaminase), which presumably increased amino acid concentration in leaves and phloem sap under elevated CO(2). In contrast, aphid infested dnf1 plants had decreased activities of N assimilation-related enzymes and transmination-related enzymes and amino acid concentrations under elevated CO(2). Furthermore, elevated CO(2) up-regulated expression of genes relevant to amino acid metabolism in bacteriocytes of aphids associated with Jemalong, but down-regulated those associated with dnf1. Our results suggest that pea aphids actively elicit host responses that promote amino acid metabolism in both the host plant and in its bacteriocytes to favor the population growth of the aphid under elevated CO(2).

Muscle Kinetics and Exercise: Any Advantages of Dietary Proteins

Muscle Kinetics and Exercise: Any Advantages of Dietary Proteins

Effects of Extrusion Conditions on the Physicochemical Properties of Extruded Red Ginseng

The effects of variable moisture content, screw speed and barrel temperature on the physicochemical properties of red ginseng powder extrudates were investigated. The raw red ginseng powders were processed in a co-rotating intermeshing twin-screw extruder. Primary extrusion variables were feed moisture content (20 and 30%), screw speed (200 and 250 rpm) and barrel temperature (115 and 130°C). Extruded red ginseng showed higher crude saponin contents (6.72~7.18%) than raw red ginseng (5.50%). Tested extrusion conditions did not significantly affect the crude saponin content of extrudates. Increased feed moisture content resulted in increased bulk density, specific length, water absorption index (WAI), breaking strength, elastic modulus and crude protein content and decreased water solubility index (WSI) and expansion (p<0.05). Increased barrel temperature resulted in increased total sugar content, but decreased reducing sugar content in the extrudate (p<0.05). Furthermore, increased barrel temperature resulted in increased amino acid content and specific length and decreased expansion and bulk density of extrudates only at a higher feed moisture content. The physicochemical properties of extrudates were mainly dependent on the feed moisture content and barrel temperature, whereas the screw speed showed a lesser effect. These results will be used to help define optimized process conditions for controlling and predicting qualities and characteristics of extruded red ginseng.

A combination of two lactic acid bacteria improves the hydrolysis of gliadin during wheat dough fermentation

The evaluation of gliadin hydrolysis during dough fermentation by using two lactic acid bacteria, Lactobacillus plantarum CRL 775 and Pediococcus pentosaceus CRL 792, as pooled cell suspension (LAB) or cell free extract (CFE) was undertaken. The CFE pool produced a greater (121%) increase in amino acid concentration than the LAB pool (70–80%). These results were correlated with the decrease (76,100 and 64,300 ppm) in the gliadin concentration of doughs supplemented with CFE and LAB, respectively, compared to control doughs. The use of LAB peptidases seemed to be a viable technologic alternative to reduce the gliadin concentration in wheat dough without using living bacteria as starter.

Effects of bovine milk ingestion on urinary excretion of oxypurinol and uric acid

Although allopurinol is a xanthine oxidase inhibitor, its overall effect may be due to the action of oxypurinol, a metabolite of allopurinol and another xanthine oxidase inhibitor, since the biological half-life of oxypurinol is longer than that of allopurinol. Oxypurinol shares a renal transport pathway with uric acid and ingestion of bovine milk increases the urinary excretion of uric acid. Therefore, we investigated whether its ingestion promotes the urinary excretion of oxypurinol. Bovine milk (15 ml/kg body weight) was administered to 6 healthy subjects who took allopurinol (300 mg) 12 h prior to ingestion. In addition, a control experiment was performed with the same subjects using the same protocol, except for the ingestion of water instead of bovine milk. Blood and urine samples were collected before and after bovine and water ingestion. In the bovine milk ingestion experiment, the urinary excretion values of oxypurinol and uric acid were increased by 18% and 38%, respectively, and the fractional excretion values of oxypurinol and uric acid were increased by 20% and 40%, respectively, whereas those did not change in the control experiment. In addition, the concentration of alanine and sum of concentrations of amino acids were increased by 16% and 20%, respectively, in the bovine milk ingestion experiment. These results suggest that bovine milk ingestion promotes the urinary excretion of oxypurinol as well as uric acid by increasing amino acid concentration.

Escherichia coli responds with a rapid and large change in growth rate upon a shift from glucose-limited to glucose-excess conditions

Glucose pulse experiments at seconds time scale resolution were performed in aerobic glucose-limited Escherichia coli chemostat cultures. The dynamic responses of oxygen-uptake and growth rate at seconds time scale were determined using a new method based on the dynamic liquid-phase mass balance for oxygen and the pseudo-steady-state ATP balance. Significant fold changes in metabolites (10–1/10) and fluxes (4–1/4) were observed during the short (200 s) period of glucose excess. During glucose excess there was no secretion of by-products and the increased glucose uptake rate led within 40 s to a 3.7 fold increase in growth rate. Also within 40–60 s a new pseudo-steady-state was reached for both metabolite levels and fluxes. Flux changes of reactions were strongly correlated to the concentrations of involved compounds. Surprisingly the 3.7 fold increase in growth rate and hence protein synthesis rate was not matched by a significant increase in amino acid concentrations. This poses interesting questions for the kinetic factors, which drive protein synthesis by ribosomes.