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At least 343 records · Page 19Linked to original sources
PubMed1981

Developmental changes of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid in different brain regions and spinal cords of rat and guinea pig.

The developmental changes of N-acetylaspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu), and beta-citryl-L-glutamic acid (beta-CG) have been examined in the cerebrum, cerebellum, brain stem and spinal cord of both rat and guinea pig by the gas chromatographic method developed in our studies. A rapid increase in the concentration of NA-Asp was observed postnatally in every region of the rat brain. On the other hand, all regions of guinea pig brain showed the prenatal increases. NA-Asp-Glu showed a different developmental profile, depending on region of the brain, in the two species. The concentration of NA-Asp-Glu remained constantly low during brain maturation in the rostral regions. In the caudal portions it showed a marked increase during maturation and reached a high level in the adult brain. The concentration of beta-CG was highest at birth in all regions of rat brain and rapidly decreased by 20 days after birth and remained low thereafter. The rapid decrease occurred in the guinea pig during the foetal period, and beta-CG content decreased to an adult level at birth.

Aging↗
PubMed1986

In vivo action of enzyme-activated irreversible inhibitors of glutamic acid decarboxylase and gamma-aminobutyric acid transaminase in retina vs. brain.

The effects of low s.c. doses of gamma-acetylenic gamma-aminobutyric acid (GAG) on glutamic acid decarboxylase (GAD) and gamma-aminobutyric acid transaminase (GABA-T) activities, as well as of gamma-vinyl GABA (GVG) and gabaculine on GABA-T activities, were examined using preparations from retina and several other regions of rat central nervous system (CNS). GAG, in doses of 5 to 50 mg/kg, inactivated retinal GAD to a significantly greater degree than GAD from any other CNS region studied. Retinal GABA-T activities were also differentially inactivated by 1 to 50 mg/kg of GAG, 50 mg/kg of GVG, or 1 and 5 mg/kg of gabaculine. GAG, in doses of 25 and 50 mg/kg, more completely inactivated GAD and GABA-T in frontal cortex than in other brain regions. Frontal cortical GABA-T was not differentially inactivated by 10 and 50 mg/kg of GVG or 1 and 5 mg/kg of gabaculine. The effects of GAG on retinal GABA enzymes were long-lasting and not reversed by dialysis. The GAD and GABA-T activities from 1:1 mixes of control and GAG-treated retinal preparations were comparable to the means of the GAG-treated and control activities. The effects documented in this study, therefore, probably reflect irreversible in vivo changes. After peripheral administration, GAG, GVG and gabaculine might reach higher levels in the retina than in the brain. Alternatively, the differential effects of these compounds might be due to the relative proportions of catalytically active GABA enzymes in different CNS regions. On the basis of the foregoing results, the retina might be a particularly suitable region of the CNS for enzyme-activated irreversible inhibitors to label catalytically active enzymes of GABA metabolism.

4-Aminobutyrate Transaminase↗
PubMed1981

Use of reversed-phase high-performance liquid chromatography for simultaneous determination of glutamine synthetase and glutamic acid decarboxylase in crude extracts.

Glutamine and gamma-aminobutyric acid (GABA), formed from glutamic acid in crude tissue extracts by glutamine synthetase and glutamic acid decarboxylase respectively, were separated by derivatization with dansyl chloride followed by reversed-phase high-performance liquid chromatography on the Altex Ultrasphere ODS-5 column. The mobile phase was a gradient of 100 mM potassium dihydrogen phosphate (pH 2.1) with 0-40% acetonitrile. The amounts of glutamine and GABA formed from glutamic acid were determined under different reaction conditions.

Animals↗
PubMed2001

Simultaneous determination of several amino acids, including homocysteine, cysteine and glutamic acid, in human plasma by isocratic reversed-phase high-performance liquid chromatography with fluorimetric detection.

A method for the simultaneous measurement of two biologically important thiol compounds cysteine and homocysteine and five amino acids including neurotransmitters aspartate and glutamate is reported. This method utilized derivatization of compounds with o-phthalaldehyde in the presence of 2-mercaptoethanol following alkylation of the free sulfydryl group with iodoacetic acid followed by separation using reversed-phase high-performance liquid chromatography. These o-phthalaldehyde-2-mercaptoethanol-labeled compounds were separated within 30 min on a Spherisorb ODS-2 column with isocratic elution using 17% methanol, 0.04 M sodium phosphate buffer (pH 7.0), 0.002 M Na2EDTA and detected fluorimetrically (excitation 340 nm, emission 450 nm). Using this method, the concentrations of homocysteine, cysteine, glutamic acid. aspartic acid, asparagine, serine and glutamine in human plasma were determined.

Cardiovascular Diseases↗
PubMed1975

Effects of D-, DL-and L-glutamic acid on chicks.

Studies were conducted to investigate the effects of D-, DL-, or L-glutamic acid on the chick. Supplementation of levels of L-glutamic acid to an amino acid mixture containing adequate levels of all the indispensable amino acids plus cystine and tyrosine resulted in increased growth up to 10% L-glutamic acid in the diet. Chicks tolerated as much as 15% L-glutamic acid with no growth retardation. Supplementation of D-glutamic acid at levels of 3.75 or 5% resulted in growth depressions of 18 and 38%, respectively, at the end of a 2-week experiment. Significant growth-depressing effects of these levels of D-glutamic acid and 7.5% of DL-glutamic acid were also observed with an amino acid diet as well as an isolated soybean protein diet. The growth-depressing effect was most severe during week 2 of the experiment. Additional vitamins and amino acid supplements failed to reverse the growth-depressing effect. Plasma glutamic acid concentration was not altered by the inclusion of D-glutamic acid in the diet, but generally, plasma free amino acid concentrations were increased. This was especially true of arginine. Free glutamic acid increased in the kidney and was lowered in the liver. Free ammonia was increased in both the liver and kidney when the D form was included in the diet. Implications of these findings are discussed.

Amino Acids↗
PubMed1981

A gas chromatographic method for the determination of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid and their distributions in the brain and other organs of various species of animals.

A simple and sensitive gas-chromatographic method for the determination of N-acetyl-L-aspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu) and beta-citryl-L-glutamic acid (beta-CG) was developed. The organ, regional and phylogenetic distributions of these compounds were studied. NA-Asp and NA-Asp-Glu were highly concentrated in nervous tissue, and less than 1% of the amounts in the nervous tissues were found in non-nervous organs. These two compounds showed a reciprocal relationship in their regional distribution in mature brains, but such a relationship was not evident or was even reversed in immature brains. The two compounds also showed different developmental changes in different regions of the brain. Fish brain contained a relatively high concentration of NA-Asp, but only a trace amount of NA-Asp-Glu. By contrast, a 10 times higher concentration of NA-Asp-Glu than NA-Asp was found in frog brain. Reptilian brain contained similar amounts of each compound. Avian and mammalian brain had NA-Asp at a roughly 10 times higher concentration than NA-Asp-Glu. beta-CG occurred at the highest concentration in the immature brain of rat and guinea pig, but disappeared in the mature brains. The adult frog brain, however, contained a large amount of beta-CG. In the adult rat, testis contained the highest concentration of beta-CG.

Aging↗
PubMed1980

Amino acid concentration in plasma after gastro-intestinal, intraportal and intravenous administration of glutamic acid.

Three groups of dogs with two dogs in each group were given a solution of glutamic acid by three different routes: gastrointestinally, intraportally and intravenously. Free plasma amino acid concentrations were determined in arterial blood and peripheral, portal and hepatic venous blood. Blood sampling was performed before, during and after the two-hour infusion period. Most amino acids did not change in plasma concentration during the experiment. Glutamic acid increased to very high concentration levels during parenteral infusion but also during gastro-intestinal ingestion in spite of the known metabolism of that amino acid in the intestinal mucosa. Alanine, which is known to originate in the mucosa from transaminated glutamic acid, increased more in portal venous blood in the gastro-intestinal group than in the other two groups. Plasma alanine levels were higher in peripheral venous blood than in any other blood vessel, when the glutamic acid infusion was administered parenterally, indicating a peripheral alanine production rather than an intestinal release. Glutamine decreased slightly during the infusions by all three routes and showed a tendency to increase after ending the infusions. There was also a tendency towards an increase in the branched chain amino acids throughout the experimental period in all three groups.

Administration, Oral↗
PubMed1980

Perinatal changes in amino acid metabolism of rat brain, especially alanine and glutamic acid.

The changes in both the levels of some free amino acids and their metabolism in the rat brain during the first 24 hr of postnatal life were studied. The content of glutamic acid decreased for the first 2 hr; it remained at the lowest level for the next 4 hr, when it began to increase. The content of alanine decreased for the first 6 hr and approached the adult level. Oxygen consumption, glucose oxidation, and pyruvate formation in the cerebral slices of the 24-hr-old rats were as much as 150% of that of the 19-day-old fetus. The distribution profile of radioactivity incorporated into the cerebral amino acids from the subarachnoid-injected [U-14C]glucose was also changed. In the 2- and 6-hr-old rats, 50% of the total radioactivity recovered in the free amino acids was in alanine. Its rate decreased to 30% in the 24-hr-old and was 2% in the adult, while the radioactivity incorporated into glutamic acid increased. Alanine aminotransferase activity started to increase at birth and had the highest level at 24 hr after birth. It then decreased and finally reached the same level as shown at birth. However, aspartate aminotransferase increased during the first 6 hr after birth and did not change until the end of the first day of life.

Aging↗
PubMed1975

Citrate synthaseless glutamic acid auxotroph of Saccharomyces cerevisiae.

Relationship of citrate synthase (EC 4.1.3.7) to the biosynthesis of glutamic acid was investigated by characterizing a new glutamic acid auxotroph FL100-D1 (glu 3) of Saccharomyces cerevisiae. Nutritional requirement of the mutant was satisfied by L-glutamic acid, L-glutamic acid peptide as well as several analogs of glutamic acid, but not by proline, ornithine, arginine, lysine or aspartic acid. The mutant was unable to utilize nonfermentable carbon sources, glycerol, acetate or lactate. Mutant glu3 unlike aconitaseless glutamic acid auxotroph glu 1, failed to accumulate 14C-citric acid in vivo from 1-14C-sodium acetate or U-14C-glutamic acid. Both spectrophotometric and radioactive assay procedures demonstrated a lack of significant citrate synthase activity in the dialysed extract of the mutant compared to the wild type strain. Mutant glu 3 complemented with glu 1 and glu 2 individually in vivo and exhibited a significant aconitase (EC 4.2.1.3) activity in vitro.

Chromatography↗
PubMed1984

Improved tolerance of vincristine by glutamic acid. A preliminary report.

In a murine model system, glutamic acid has demonstrated host protective properties during administration of vincristine (VCR). Subsequently, glutamic acid has been evaluated in patients receiving VCR during adjuvant chemotherapy for stage II carcinoma of the breast. The cumulative VCR dosage and toxicities incurred in 16 patients receiving glutamic acid have been compared to those observed in 88 patients who previously received VCR without glutamic acid in the same chemotherapy program. All patients received VCR 1.0 mg/m2 weekly for 6 weeks with dose modification for neurotoxicity. Treatment patients received glutamic acid 1.5 grams p.o. daily in three divided doses during the induction course. Of the 16 treatment patients, 9 (56%) received 100% ideal dosage of VCR during induction therapy whereas only 24 of 88 (27%) comparison patients attained this dosage level (p less than .025). Gastrointestinal and hematologic toxicities were similar in both groups. These preliminary results suggest the need for an expanded trial of this agent during administration of VCR.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Biomedical applications of chemically and microbiologically synthesized poly(glutamic acid) and poly(lysine).

This review article deals with the synthesis, physiochemical properties, and potential biomedical applications of two homo-poly amino acids. Poly-alpha-glutamic acid (alpha-PGA) and poly-alpha-lysine (alpha-PL) were synthesized by chemical synthesis. poly-gamma-glutamic acid (gamma-PGA) and poly-epsilon-lysine (epsilon-PL) were naturally occurring bio-materials that were produced by microbial fermentation. Poly(glutamic acid) (PGA) and poly(lysine) (PL) are water soluble, biodegradable, edible and nontoxic toward humans and the environment. As a result, they are suitable for various applications and have recently attracted considerable interest of the chemical industry. The distinguished features of PGA and PL also make them promising candidates for biomedical applications. The applications of PGA and PL in the areas of biomedical materials, drug delivery carriers and biological adhesives have been studied extensively and will be discussed in this review.

Adhesiveness↗
PubMed1985

The digestion by cattle of silage-containing diets fed at two dry matter intakes. 2. Digestion of total amino acids and of D-alanine and D-glutamic acid.

In a 4 X 4 Latin square experiment four cows were given, twice daily, diets consisting of (g/kg dry matter (DM)) 500 barley, 400 grass silage and 100 soya-bean meal. The diets were given at either 1.15 (L) or 2.3 (H) times maintenance energy requirements and the soya-bean meal was either untreated (U) or formaldehyde (HCHO)-treated (T). The passage of digesta to the duodenum was estimated using chromic oxide as a flow marker; 35S was used to estimate the amount of microbial protein entering the small intestine. A microbial fraction was prepared by differential centrifugation from duodenal digesta. Samples of bacteria and of protozoa from rumen digesta were also prepared. The total amino acid contents of feedingstuffs, duodenal digesta, duodenal microbial material, rumen bacteria and rumen protozoa were determined by ion-exchange chromatography. The D-alanine and D-glutamic acid contents of the samples were determined by gas-liquid chromatography. The quantity of each amino acid entering the small intestine was significantly (P less than 0.001) increased by increasing DM intake and tended to be increased by formaldehyde-treatment of the soya-bean meal. There were net losses of all amino acids across the forestomachs except for lysine, methione, D-alanine and D-glutamic acid for which there were net gains. There were significant (P less than 0.05) differences in amino acid composition between rumen bacteria and duodenal microbial material; differences in amino acid composition between rumen bacteria and rumen protozoa were also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1972

Glutamic acid as a precursor to N-terminal pyroglutamic acid in mouse plasmacytoma protein (protein synthesis-initiation-immunoglobulins-pyrrolidone carboxylic acid).

Cell suspensions derived from a mouse plasmacytoma (RPC-20) that secretes an immunoglobulin light chain containing N-terminal pyroglutamic acid can synthesize protein in vitro. Chromatographic examination of an enzymatic digest of protein labeled with glutamic acid shows only labeled glutamic acid and pyroglutamic acid; hydrolysis of protein from cells labeled with glutamine, however, yields substantial amounts of glutamic acid in addition to glutamine and pyroglutamic acid. The absence of glutamine synthetase and presence of glutaminase in plasmacytoma homogenates is consistent with these findings. These data indicate that N-terminal pyroglutamic acid can be derived from glutamic acid without prior conversion of glutamic acid to glutamine. Since free or bound forms of glutamine cyclize nonezymatically to pyroglutamate with ease, while glutamic acid does not, the data suggest that N-terminal pyroglutamic acid formation from glutamic acid is enzymatic rather than spontaneous.

Amino Acyl-tRNA Synthetases↗
PubMedDate not supplied

Effects of aging and dementia on the levels of thiobarbituric-acid-reactive products stimulated by L-glutamic acid in human autopsy and biopsy brain tissue.

Basal and stimulated (by L-glutamic acid, GA) levels of thiobarbituric-acid-reactive products were estimated in the brain tissue (hippocampus, cortex and cerebellum) from autopsy samples of people with Alzheimer disease (AD), multi-infarct dementia (MID) and from nondemented control patients. The experiment was also performed on biopsy brain tissue (cortex) of nondemented controls. The biopsy brain tissue influenced by normal aging in vivo showed a limited susceptibility to undergo lipid peroxidation stimulated by GA in vitro in comparison with the younger tissue. A significant decrease in the ratio of stimulated to basal levels was found in the cerebellum of MID patients in comparison with nondemented controls and AD patients.

Aged↗
PubMed2004

Glutamic acid removal and PHB storage in the activated sludge process under dynamic conditions.

Glutamic acid removal in the activated sludge process is studied herein, primarily the formation of storage polymers under dynamic conditions. The activated sludge process was operated by using a sequencing batch reactor (sludge age of 6 d) fed with a synthetic mixture of readily available carbon sources, including glutamic acid. Removal of glutamic acid as the only carbon sources was studied in batch tests, along with oxygen consumption, ammonia uptake-release, and formation of storage polymers. It was found that poly-3-hydroxybutyrate (PHB) was stored and that the storage also occurred simultaneously to biomass growth. PHB storage accounted for 16% of the overall solids that were formed from glutamic acid, as the average value of nine batch tests. Neither other Polyhydroxyalkanoates nor polyglutamic acid were detected. Nuclear magnetic resonance analysis, performed on biomass extracts, allowed us to clarify the main metabolic pathways involved in glutamic acid removal and, in particular, the pathways involved in PHB storage. It was found that glutamic acid enters the Krebs cycle as alpha-ketoglutaric acid and exits to form pyruvic acid and then acetyl-CoA, which is the starting point of PHB production pathway.

Ammonia↗
PubMed1983

Pathways of L-glutamic acid transport in cultured human fibroblasts.

The transport of L-glutamic acid has been studied in skin-derived diploid human fibroblasts. Competition analysis in the presence and absence of Na+ and mathematical discrimination by nonlinear regression indicated that L-glutamic acid enters the cell by at least three transport systems: 1) a high affinity Na+-dependent system which has been found to be identical to the previously described system for anionic amino acids (Gazzola, G. C., Dall'Asta, V., Bussolati, O., Makowske, M., and Christensen, H. N. (1981) J. Biol. Chem. 256, 6054-6059) and which is provisionally designated as System X-AG; this route was shared by L-aspartic acid; 2) a low affinity Na+-dependent system resembling the ASC System for neutral amino acids (Franchi-Gazzola, R., Gazzola, G. C., Dall'Asta, V., and Guidotti, G. G. (1982) J. Biol. Chem. 257, 9582-9587); its reactivity toward L-glutamic acid was strongly inhibited by L-serine, but not by 2-(methyl-amino)isobutyric acid; and 3) a Na+-independent system similar to System XC- described in fetal human lung fibroblasts (Bannai, S., and Kitamura, E. (1980) J. Biol. Chem. 255, 2372-2376). The XC- system served for L-glutamic acid and L-cystine, the latter amino acid behaving as a potent inhibitor of L-glutamic acid uptake. Amino acid starvation did not change the uptake of L-glutamic acid by the two Na+-dependent systems, but enhanced the activity of System XC- by increasing its Vmax. L-Glutamic acid transport was also affected by the density of the culture. An increased cell density lowered the uptake of the amino acid by Systems ASC and XC- and promoted the uptake by System X-AG. All these variations were dependent upon changes in Vmax.

Aminoisobutyric Acids↗