High Glutamic Acid Research Articles

Independent and Additive Effects of Glutamic Acid and Methionine on Yeast Longevity

It is established that glucose restriction extends yeast chronological and replicative lifespan, but little is known about the influence of amino acids on yeast lifespan, although some amino acids were reported to delay aging in rodents. Here we show that amino acid composition greatly alters yeast chronological lifespan. We found that non-essential amino acids (to yeast) methionine and glutamic acid had the most significant impact on yeast chronological lifespan extension, restriction of methionine and/or increase of glutamic acid led to longevity that was not the result of low acetic acid production and acidification in aging media. Remarkably, low methionine, high glutamic acid and glucose restriction additively and independently extended yeast lifespan, which could not be further extended by buffering the medium (pH 6.0). Our preliminary findings using yeasts with gene deletion demonstrate that glutamic acid addition, methionine and glucose restriction prompt yeast longevity through distinct mechanisms. This study may help to fill a gap in yeast model for the fast developing view that nutrient balance is a critical factor to extend lifespan.

전통 가양주인 황금주의 품질 특성

The quality characteristics of Hwanggeumju (a type of traditional Korean rice wine), which has been described in an ancient document (Sangayorok), were investigated. During its fermentation, its pH gradually decreased from 4.23 to 3.96); and after four days of fermentation, its sugar content significantly decreased. After seven days, its alcohol content rapidly increased to 15.8 percent. Its major organic acid is lactic acid, but malic, succinic, citric and acetic acid were also detected in it. The free amino acid analysis showed relatively high alanine, arginine, asparagine, glutamic acid and leucine contents. The sensory evaluation resulted in high scores for color, turbidity and taste.

Study on the Directional Breeding of High Glutamic-Acid Production Strain GTS190 and the Control on its Fermentation

Using Brevibacterium flavum CN1021 as starting strain, the L-glutamate producing strain was directionally bred with protoplast UV mutagenesis, UV mutagenesis and DES mutagenesis. Through shake-tube preliminary screening, shake-flask re-screening, genetic markers verification and continuous passage, an L-glutamate temperature-sensitive mutant strain GTS190 (Ts+Omr+GluHXr+ SGr+FEAr+AECr+Sucg) was screened finally. It was fermented for 36h in a vessel (30L) feeding by batches, in which glutamic acid production reached 195g/L and sugar and acid conversion rate was 66%.

저온 및 고온살균 사과주스의 품질 특성

The physiochemical property, nutrient composition, and functionality of apple juice sterilized at a low temperature (LT, , 30 min) or a high temperature (HT, , 20 min) were analyzed. The pH of the apple juice that was sterilized at LT (pH 4.72) was higher than that of the apple juice that was sterilized at HT (pH 4.57), and the acidity of the apple juice that was sterilized at HT (8.90%) was higher than that of the other sample. The sugar content of the two apple juice samples was 15 , and the apple juice samples had high potassium, malic acid, and glutamic acid contents. The total polyphenol contents of the apple juice samples that were sterilized at LT and HT were 27.39 mg/100 mL and 23.24 mg/100 mL, respectively. The apple juice that was sterilized at LT had a significantly stronger DPPH radical scavenging activity than the apple juice that was sterilized at HT (

Pharmacokinetically Stabilized Cystine Knot Peptides That Bind Alpha-v-Beta-6 Integrin with Single-Digit Nanomolar Affinities for Detection of Pancreatic Cancer

Detection of pancreatic cancer remains a high priority and effective diagnostic tools are needed for clinical applications. Many cancer cells overexpress integrin α(v)β(6), a cell surface receptor being evaluated as a novel clinical biomarker. To validate this molecular target, several highly stable cystine knot peptides were engineered by directed evolution to bind specifically and with high affinity (3-6 nmol/L) to integrin α(v)β(6). The binders do not cross-react with related integrin α(v)β(5), integrin α(5)β(1), or tumor-angiogenesis-associated integrin, α(v)β(3). Positron emission tomography showed that these disulfide-stabilized peptides rapidly accumulate at tumors expressing integrin α(v)β(6). Clinically relevant tumor-to-muscle ratios of 7.7 ± 2.4 to 11.3 ± 3.0 were achieved within 1 hour after radiotracer injection. Minimization of off-target dosing was achieved by reformatting α(v)β(6)-binding activities across various natural and pharmacokinetically stabilized cystine knot scaffolds with different amino acid content. We show that the primary sequence of a peptide scaffold directs its pharmacokinetics. Scaffolds with high arginine or glutamic acid content suffered high renal retention of more than 75% injected dose per gram (%ID/g). Substitution of these amino acids with renally cleared amino acids, notably serine, led to significant decreases in renal accumulation of less than 20%ID/g 1 hour postinjection (P < 0.05, n = 3). We have engineered highly stable cystine knot peptides with potent and specific integrin α(v)β(6)-binding activities for cancer detection. Pharmacokinetic engineering of scaffold primary sequence led to significant decreases in off-target radiotracer accumulation. Optimization of binding affinity, specificity, stability, and pharmacokinetics will facilitate translation of cystine knots for cancer molecular imaging.

Effect of Pre-Germination Time on Amino Acid Profile and Gamma Amino Butyric Acid (GABA) Contents in Different Varieties of Malaysian Brown Rice

Eighteen varieties of Malaysian brown rice were evaluated for their crude protein, total glutamic acid, and gamma amino butyric acid contents after pre-germination at different times. The crude protein and total glutamic acid content increased significantly in all the varieties after pre-germination. Gamma amino butyric acid content increased dramatically with time during the pre-germination process. A significant (p < 0.05) positive correlation was observed between protein, glutamic acid, and gamma amino butyric acid contents before and after pre-germination. The brown rice varieties containing higher glutamic acid and/or protein content before the pre-germination process provided more gamma amino butyric acid content during pre-germination.

Heterogeneity among patients with latent autoimmune diabetes in adults

Some type 1 diabetic patients do not require insulin at diagnosis of diabetes, and they progress to insulin dependence only after several years (latent autoimmune diabetes in adults). However, not all patients with latent autoimmune diabetes in adults progress to insulin dependence. We compared the characteristics of patients with high glutamic acid decarboxylase antibodies (GADA) titres (≥10 U/mL) to those of patients with low titres and examined other factors possibly associated with the progression to insulin dependence. We began registering diabetic patients in 1993 and have since followed them prospectively. Among these patients, we analysed clinical characteristics and progression to insulin dependence in those followed for more than 5 years. Patients with high GADA titres were younger and had lower body mass index, shorter disease durations and lower serum C-peptide (s-CPR) levels than the patients with low GADA titre and GADA negative type 2 diabetes. Frequencies of other islet-related autoantibodies were significantly higher in patients with high GADA titre than in those with low GADA titres. Disease protective HLA class II genotypes were less frequent in patients with high titre. The positive predictive value of being GADA positive was only 42.7%. The positive predictive value increased to 78.6% when the cut-off was set at the relatively high level of 10 U/mL. Combining GADA with other islet-related autoantibodies or HLA class II genotype increased positive predictive value but decreased sensitivity. Our results suggest that latent autoimmune diabetes in adults constitutes a heterogeneous group and that the majority of patients with high GADA titres (≥10 U/mL) will ultimately develop type 1 diabetes while those with low titres include patients with type 1 and type 2 diabetes.

Use of Tetragenococcus halophilus as a Starter Culture for Flavor Improvement in Fish Sauce Fermentation

The potential of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation was elucidated. Four strains of T. halophilus isolated from fish sauce mashes were inoculated to anchovy mixed with 25% NaCl with an approximate cell count of 10(6) CFU/mL. The α-amino content of 6-month-old fish sauce samples inoculated with T. halophilus was 780-784 mM. The addition of T. halophilus MRC10-1-3 and T. halophilus MCD10-5-10 resulted in a reduction of histamine (P < 0.05). Fish sauce inoculated with T. halophilus showed high contents of total amino acids with predominantly high glutamic acid. Major volatile compounds in fish sauce were 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde. T. halophilus-inoculated fish sauce samples demonstrated the ability to reduce dimethyl disulfide, a compound contributing to a fecal note. The use of T. halophilus for fish sauce fermentation improves amino acid profiles and volatile compounds as well as reduces biogenic amine content of a fish sauce product.

Effect of drying and proline addition on aroma volatile compounds of acid‐hydrolysed rice bran protein concentrate

SummaryRice bran protein concentrate (RBPc) was hydrolysed by 0.5 N aqueous HCl at 95 °C for 12 h. The liquid hydrolysate obtained was prepared as hydrolysate powder by spray drying. Aroma volatile compounds in liquid hydrolysate and its hydrolysate powder were tentatively identified by GC‐MS. Furfural and vanillin were found in both hydrolysates with high concentration, and vanillin showed the highest odour activity value. Hexanal was present in only liquid hydrolysate. Concentrations of carboxylic acids and heterocyclic compounds, especially 2‐methoxy‐6‐methylpyrazine, increased after drying. Amino acid composition of the hydrolysate powder showed high aspartic acid and glutamic acid. Aroma volatile compounds of hydrolysate powder prepared by the addition of proline at pH 6.0 (Pro6.0‐H) and pH 7.5 (Pro7.5‐H) before drying were investigated. Furaneol was found only in Pro6.0‐H, but it was not detected in Pro7.5‐H and hydrolysate powder without proline addition. Pro7.5‐H had higher furfural and vanillin concentrations than Pro6.0‐H.

Acute metabolic encephalopathy in two patients treated with asparaginase and ondasetron

L-asparaginase has been an important agent of acute lymphoblastic leukemia (ALL) therapy for more than 40 years. The major adverse events of L-asparaginase are immunoallergic reaction, pancreatitis, liver cytolysis (increased ASAT, ALAT, and bilirubin), and cerebral haemorrhage or thrombosis. Hyperammonemia has already been described with L -asparaginase treatment [1]. In the present article, we report acute metabolic encephalopathy in two young boys receiving asparaginase for B ALL relapse. We discuss the pathophysiology of this metabolic encephalopathy with hyperammonemia and its medical management.

Limbic encephalitis in children and adolescents

ObjectiveLimbic encephalitis is rare in people <18 years of age and rarely given a formal diagnosis.DesignRetrospective study on presentation and outcome of children and adolescents with the clinico-radiological syndrome of...

The analysis of selected neurotransmitter concentrations in serum of patients with Tourette syndrome

Background and purposeMetabolic disturbances of excitatory and inhibitory neurotransmitters are implicated in pathogenesis of Tourette syndrome (TS). The aim of the study was to measure serum concentrations of glutamic acid, γ-aminobutyric acid (GABA) and glycine in TS patients and evaluate any correlation between neurotransmitter levels and age at onset, actual age, gender, tic severity, duration of the disease and concomitant psychiatric disorders. Material and methodsSixty-seven TS patients, aged 16–59, and 57 healthy controls, aged 19–37, were enrolled in the study. Information regarding medical history and physical investigation was collected using a short questionnaire. Sixty-seven percent of patients were medication-free at the time of examination and the rest had withheld treatment for 24 hours before. Blood samples were taken after a 12-hour fasting period. HPLC technique was used. ResultsThe TS group had higher glutamic acid and lower GABA levels. Glycine concentrations were comparable. No differences regarding neurotransmitter concentrations between treated and non-treated patients were found. Patients with concomitant obsessive-compulsive disorder and severe tics had higher glutamate levels. Glutamate concentrations correlated positively with the number of comorbid psychiatric disorders and GABA concentrations correlated negatively with the number of behavioural problems in patients with comorbidities. There was no correlation between analysed neurochemicals and age, gender, age at onset or disease duration. ConclusionsImbalance between excitatory and inhibitory systems in the brains of TS patients may be reflected by glutamate and GABA serum level changes. Glutamate and GABA may be biomarkers of the disease and high concentration of glutamate may indicate more severe course of TS.

Activation of the SspA Serine Protease Zymogen of Staphylococcus aureus Proceeds through Unique Variations of a Trypsinogen-like Mechanism and Is Dependent on Both Autocatalytic and Metalloprotease-specific Processing

The serine and cysteine proteases SspA and SspB of Staphylococcus aureus are secreted as inactive zymogens, zSspA and zSspB. Mature SspA is a trypsin-like glutamyl endopeptidase and is required to activate zSspB. Although a metalloprotease Aureolysin (Aur) is in turn thought to contribute to activation of zSspA, a specific role has not been demonstrated. We found that pre-zSspA is processed by signal peptidase at ANA(29) downward arrow, releasing a Leu(30) isoform that is first processed exclusively through autocatalytic intramolecular cleavage within a glutamine-rich propeptide segment, (40)QQTQSSKQQTPKIQ(53). The preferred site is Gln(43) with secondary processing at Gln(47) and Gln(53). This initial processing is necessary for optimal and subsequent Aur-dependent processing at Leu(58) and then Val(69) to release mature SspA. Although processing by Aur is rate-limiting in zSspA activation, the first active molecules of Val(69)SspA promote rapid intermolecular processing of remaining zSspA at Glu(65), producing an N-terminal (66)HANVILP isoform that is inactive until removal of the HAN tripeptide by Aur. Modeling indicated that His(66) of this penultimate isoform blocks the active site by hydrogen bonding to Ser(237) and occlusion of substrate. Binding of glutamate within the active site of zSspA is energetically unfavorable, but glutamine fits into the primary specificity pocket and is predicted to hydrogen bond to Thr(232) proximal to Ser(237), permitting autocatalytic cleavage of the glutamine-rich propeptide segment. These and other observations suggest that zSspA is activated through a trypsinogen-like mechanism where supplementary features of the propeptide must be sequentially processed in the correct order to allow efficient activation.

Relating Trypsin Enzymatic Properties with Amino Acid Composition

In this paper, the DNA fragment of trypsin genes from eight crustaceans were cloned and sequenced. The amino acid composition of the 24 deduced and 42 selected trypsin sequences were compared. Low arginine, methionine, and proline content and high aspartic acid, glutamic acid, and isoleucine content attributed to the distinct catalytic efficiency of crustacean trypsins.

Comparison of physical–chemical properties of type I collagen from different species

Type I collagen is an important biopolymer and has been widely used in biomaterials due to its excellent biocompatibility and biodegradable properties. However, only a few studies have been reported on its comparison in different species. The amino acid composition, SDS-PAGE, UV–Vis spectrum, thermal transition temperatures, extractable uronic acid/protein ratio and enzymatic sensitivity of type I collagen from bird feet (BF), bovine skin (BS), frog skin (FS), porcine skin (PS) and shark skin (SS) were evaluated. The amino acid composition of type I collagens were different from different species, BF collagen contained higher glutamic acid (Glu) and aspartic acid (Asp), SS collagen contained lower aspartic acid and hydroxyproline (Hyp). Similar SDS-PAGE profiles were found from different animal’s collagen, all samples were composed of two α1-chain and one α2-chain. All UV–Vis spectrums exhibited a typical absorption peak at 218 nm. The UV absorption spectrum of BF collagen ranged from 190 to 340 nm, FS collagen ranged from 190 to 270 nm; the other species collagen ranged from 190 to 240 nm. Thermal transition temperatures of type I collagen from different animals decreased in the order of BF > BS > PS > FS > SS. PS collagen had higher extractable uronic acid/protein ratio and the lowest enzymatic sensitivity. Summarizing these results, the BF collagen had higher hyproxyproline (Hyp) + proline (Pro) value and exhibited higher thermal stability; the PS collagen contained larger amount of glycosaminoglycan and resulted in a high enzymes resistance. However, the BF and PS collagen should be used as a suitable material in biomaterial utilitys because of its better biostability.

잠분(蠶糞) 급여가 돈육 등심의 화학적 조성에 미치는 영향

This study investigated the effects of silkworm droppings(SWD) added diet feeding on chemical composition of pork loin meat. Pigs were divided into 7 treatment groups(10 pigs/group) and subjected to one of seven treatment diets(0, 1 %, 2 %, 3 % SWD for 4 weeks, 1 %, 2 %, 3 % SWD for 8 weeks, SWD diets; total fed diets) before slaughter. Pork loin were collected from the animals(110 kg body weight) slaughtered at a com- mercial slaughter house. Pork loin meat were aerobic packaged and then stored at 4 for 2, 5, 8, or 12 ℃ days. Samples were analyzed for TBARS, sensory evaluation, myoglobin content, fatty acid composition, amino acid and mineral content. TBARS value was not significantly different between the control and SWD treatment groups. Myoglobin content of SWD fed group pork was significantly increased than that of control group(P < 0.05). Marbling score and acceptability were increased in SWD fed pork compared to those in control pork. Na, Mg, Ca, Mn and Fe content of SWD fed group pork was significantly decreased than those of control group(P<0.05). P content was significantly increased than that of control group(P < 0.05). In the change of ami- no acid composition, the contents of aspartic acid, serine and tyrosine were decreased by dietary SWD-supple- mentation, whereas the SWD-supplementation resulted in the higher glutamic acid, alanine and isoleucine. As dietary SWD was increased in feed, the content of oleic acid was significantly increased, but stearic acid was significantly decreased(P<0.05).

Mechanistic understanding of the fermentative L‐glutamic acid overproduction by Corynebacterium glutamicum through combined metabolic flux profiling and transmembrane transport characteristics

AbstractSince the 1950s when Micrococcus glutamicus later renamed Corynebacterium glutamicum was discovered, the production of amino acids by fermentative methods has become an important aspect of industrial microbiology. Numerous studies to understand and improve the metabolic conditions leading to amino acid overproduction have been carried out. Most amino acids are currently produced by use of mutants that contain combinations of auxotrophic and regulatory mutations. L‐Glutamic acid is the amino acid produced in the greatest quantities (106 tonnes per year) and Corynebacteria are central to its industrial production. However, further improvements to strain performance are difficult to obtain by empirical optimization and a more rational approach is required. The use of metabolic flux analysis provides valuable information regarding bottlenecks in the formation of desired metabolites. Such techniques have found application in elucidating flux control, provided insight into metabolic network function and developed methods to amplify or redirect fluxes in engineered bioprocesses. Hence, branch points in biosynthesis, precursor supply in fuelling reactions and export of metabolites can be manipulated, resulting in high glutamic acid overproduction by Corynebacterium glutamicum fermentations. In this review, in addition to reviewing the state of play in metabolic flux analysis for glutamate overproduction, the metabolic pathways involved in the production of L‐glutamic acid, the mechanisms mediating its efflux and secretion as well as their manipulation to achieve higher glutamate production, are discussed. The link between metabolic flux and transmembrane transport of glutamic acid are also considered. Copyright © 2004 Society of Chemical Industry

Chemical and Nutrient Analysis of Baobab (Adansonia digitata) Fruit and Seed Protein Solubility

The baobab seed and pulp were analyzed for proximate composition, mineral content, and amino acid composition. The seed oil and protein were evaluated for their fatty acid profile and protein solubility. The seed was found to be a good source of energy, protein, and fat. Both the kernel and the pulp contain substantial quantities of calcium, potassium, and magnesium. Amino acid analyses revealed high glutamic and aspartic acid contents and the sulfur-containing amino acids as being the most limited amino acid. The fatty acid profile showed that oleic and linoleic were the major unsaturated fatty acids, whereas palmitic was the major saturated acid. Of the several solvents tested to solubilize the seed protein, 0.1 M NaOH was found to be the most effective. The protein was more soluble at alkaline than acidic pH. with the lowest solubility at pH 4.0.

Functional characterization of a salt- and thermotolerant glutaminase from Lactobacillus rhamnosus

The deamination of glutamine is a crucial step in the production of enzymatically hydrolyzed plant proteins to reach high glutamic acid yields. The required glutaminase activity usually is provided by addition of technical enzymes or by in situ generation from fungi, yeast or bacteria (i.e. Aspergillus oryzae in soy sauce production). We screened food-grade Lactobacilli for potential glutaminase activity and selected the enzyme found in Lactobacillus rhamnosus for further characterization. Glutaminase from L. rhamnosus was induced by growing the microorganism on hydrolyzed wheat gluten, a glutamine-rich protein source. Glutamine deaminating activity (glutaminase, EC 3.5.1.2) was found to be membrane-bound and lost its activity gradually upon solubilization. Functional studies of the glutaminase showed an optimal working pH of 7.0 and maximum activity at 50 °C. High salt-tolerance of the enzyme was observed, i.e. the presence of 5% (w/v) salt increased glutaminase activity almost two-fold and 90% of the initial activity still remained at 15% (w/v) salt. The glutaminase activity showed typical Michaelis–Menten behavior with an affinity constant K m of 4.8±0.4 mM for glutamine and a V max of 101±2 U/l.

EFFECT OF MOLYBDENUM APPLICATIONS ON CONCENTRATIONS OF FREE AMINO ACIDS IN WINTER WHEAT AT DIFFERENT GROWTH STAGES

ABSTRACT A pot experiment with winter wheat was conducted on a yellow- brown acid soil collected from Xinzhou, Hubei Province, China. The free- and protein-amino acid concentrations in leaves of control and molybdenum (Mo)-treated winter wheat were determined at tillering, elongation, and the ear sprouting stages. Under low nitrogen (N) conditions, the free amino acid, free alanine, and glycine concentrations in winter wheat leaves at tillering and elongation stage were increased by Mo application, suggesting that N metabolism during the vegetative growth period of winter wheat was improved by Mo application. However, the free amino acid concentration of Mo-treated plants was reduced significantly at the ear sprouting stage, indicating that the Mo treated wheat was retarded by earlier N deficiency. Under high N conditions, the total free amino acid concentration of winter wheat leaves was increased at tillering, but was decreased considerably at the ear sprouting stage by applying Mo. Thus, Mo fertilizer accelerated the amino acid synthesis of winter wheat at tillering, while the N metabolism of Mo deficient wheat at the generative stage was extremely vigorous. The free glutamic acid concentration was decreased, and the free alanine, glycine, and aspartic acid concentrations were increased by Mo application, at the high N application rate. High free glutamic acid and serine concentrations in wheat were induced by Mo deficiency. Thus the transformation of glutamic acid might be handicapped under Mo deficient conditions. The sulphur-containing amino acids and the concentrations of phenylalanine, tyrosine were all increased at the elongation stage while Mo was utilized.