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PubMedDate not supplied

[Effect of glutamic acid on the course of recovery processes in the adrenal cortex].

Glutamic acid in a dose of 1/100 of the LD50 was injected in the form of sodium salt into male and female Wistar rats for 7 days after 8- and 12-day injections of dexazone. During the first 3 days of injections, female rats received a low dexazone dose (5 micrograms/100 g bw). Injection of glutamic acid in conjunction with dexazone reduced the inhibitory effect of the latter drug on the adrenals but did not avert its inhibitory effect on the central nervous system. Prolonged injections of glutamic acid after dexazone treatment promoted more rapid and more complete recovery of adrenal function.

11-Hydroxycorticosteroids↗
PubMed1981

Mass fragmentographic determination of endogenous glycine and glutamic acid released in vivo from the pigeon optic tectum. Effect of electric stimulation of a midbrain nucleus.

Various investigations suggest glycine to be an inhibitory transmitter in the pigeon optic lobe in a pathway originating in the nucleus isthmi, pars parvocellularis (Ipc) terminating in the optic tectum. In order to obtain additional evidence for this hypothesis the in vivo release of endogenous glycine in the optic tectum upon electrical stimulation of Ipc was investigated. By perfusing the upper strata of the optic tectum with Ringer solution using a push-pull cannula endogenous amino acids released from the surrounding tissue were collected. Concentration of glycine and glutamic acid in the perfusates were determined by mass fragmentography of their N-pentafluoropropionyl hexafluoroisopropyl esters. Deuterium-labeled glycine and glutamic acid were used as internal standards for quantitative measurements. The resting release of glycine and glutamic acid was 2.9 pmol/min and 1.4 pmol/min, respectively. Electrical stimulation of Ipc was found to induce a 2--40-fold increase of the glycine efflux into the perfusate whereas the efflux of glutamic acid remained at a constant level. These findings strongly support the hypothesis that glycine is a transmitter in Ipc-tectal neurons.

Animals↗
PubMed1987

Decreased glutamic acid and increased 5-hydroxytryptamine in Huntington's disease brain.

gamma-Aminobutyric acid (GABA), glutamate and serotonin (5-HT), along with its major metabolite, 5-hydroxyindoleacetic acid (5-HIAA), have been measured in 4 brain regions taken post-mortem from patients with Huntington's disease and from control subjects. GABA was found to be significantly reduced, not only in the basal ganglia, but also in the cortex and hippocampus. Glutamate was also reduced in all regions except the pallidum, and thus was unrelated to the GABA deficit which was greatest in this area. 5-HT and 5-HIAA were significantly increased in all areas except the hippocampus.

Brain Chemistry↗
PubMed1984

Effects of alpha-kainic acid, domoic acid and their derivatives on a molluscan giant neuron sensitive to beta-hydroxy-L-glutamic acid.

No identifiable giant neuron of an African giant snail (Achatina fulica Férussac) was found to be sensitive to L-glutamic acid (L-Glu). However, some of them, including the RAPN (right anterior pallial neuron), were sensitive to beta-hydroxy-L-glutamic acid (L-BHGA). The effects on RAPN of alpha-kainic acid (alpha-KA), domoic acid (DMA) and their derivatives, which are structurally related to L-Glu and L-BHGA, were examined in order to elucidate the chemical structures necessary to produce the effects under study. Erythro- and threo-L-BHGA showed similar excitatory effects on RAPN (the minimal effective concentration (M.E.C.): 10(-4)M). alpha-KA, alpha-KA methylketone and DMA also showed marked excitatory effects on the same neuron (M.E.C.: 3 X 10(-5)-10(-4)M). The two derivatives of alpha-KA, (2S, 3S, 4S)-2-carboxy-4-(1-methyl-5(R)-hydroxymethyl-l(Z),3(Z)-hexadienyl) pyrrolidine-3-acetic acid and (2S,3S,4S)-2-carboxy-4-(1-methyl-5(R)-hydroxymethyl-1(Z),3(E)-hexadie nyl) pyrrolidine-3-acetic acid, also had excitatory effects (M.E.C.: about 3 X 10(-4)M) which were somewhat less potent than those of L-BHGA, alpha-KA etc. However, alpha-allo-KA, alpha-allo-KA methylketone and dihydro-alpha-KA even at a high concentration of 4.7 X 10(-4)M, had no effect on RAPN. From the results obtained, it appears likely that the seven excitatory compounds mentioned above act on the common receptors of the RAPN neuromembrane, due to similarities in their structures and in the type of excitation caused by these compounds.

Animals↗
PubMed1991

Site-directed mutagenesis of the beta subunit of tryptophan synthase from Salmonella typhimurium. Role of active site glutamic acid 350.

To investigate the functional role of glutamic acid 350 in the active site of the beta subunit of tryptophan synthase from Salmonella typhimurium, we have replaced this residue by glutamine or alanine by use of site-directed mutagenesis. The mutant alpha 2 beta 2 complexes were expressed, purified, crystallized, and characterized by spectroscopic and kinetic studies with several substrates. We find large alterations in the substrate and reaction specificity of each mutant form of the alpha 2 beta 2 complex. Since the two mutant enzymes are virtually inactive in reactions with L-serine but are active in reactions with beta-chloro-L-alanine, glutamic acid 350 may facilitate the beta-elimination of the weak hydroxyl leaving group of L-serine. The mutant alpha 2 beta 2 complexes are more active than the wild type enzyme in the beta-elimination reaction with beta-chloro-L-alanine. These enzymes are irreversibly inactivated by beta-chloro-L-alanine, whereas the wild type enzyme is not. These altered properties may result from a change in the conformation of the active site, from a change in the orientation of the coenzyme relative to active site residues, or from a change in the solvent accessibility of the active site. The alteration in the active site may enhance the release of amino acrylate from the Schiff base intermediate by hydrolysis or by transamination.

Amino Acids↗
PubMed1986

The binding properties and regional ontogeny for [3H]glutamic acid Na+-independent and [3H]kainic acid binding sites in chick brain.

The binding kinetics, pharmacological properties and regional ontogeny of L-[3H]glutamic acid Na+-independent and [3H]kainic acid binding sites were studied in preparations of chick brain. One binding component was found for L-[3H]glutamic acid with a Kd value of 176 x 10(9) M. For [3H]kainic acid two binding components were found in the hemispheres, optic lobes and brain stem, one with high affinity and a Kd value of 12.5 x 10(9) M and one with low affinity and a Kd value of 260 x 10(9) M. In cerebellum only one binding site was detected for [3H]kainic acid with a Kd value of 144 x 10(9) M. The ontogeny of L-[3H]glutamic acid and [3H]kainic acid binding sites was studied using membrane preparations (48,000 g pellet) of hemispheres, optic lobes, brain stem and cerebellum. Binding of L-[3H]glutamic acid was already significant in all brain regions by embryonic day 11 but major increases in total receptor number per brain region or per mg of protein were apparent by embryonic day 19 and especially after hatching. Cerebral hemispheres, optic lobes and brain stem showed few [3H]kainic acid binding sites by day 13 in ovo. An increase follows which, in hemispheres and optic lobes, continues at the same rate during the first two weeks after hatching. In cerebellum, by contrast, the kainic acid binding site is almost undetectable until embryonic day 15. The appearance of these binding sites in cerebellum takes place during the restricted period between days 15 in ovo and 5 post-hatching. This pattern of development of [3H]kainic acid binding sites almost parallels the developmental patterns of the molecular layer of chick cerebellum and it is consistent with the results of our autoradiographic study showing that the great majority of kainic acid binding sites are localized in the molecular layer.

Aging↗
PubMed1989

Effects of intrahypothalamic injections of GABA, muscimol, pentobarbital, and L-glutamic acid on feed intake of satiated sheep.

Five wethers were surgically prepared with cranial implants to study the role of gabaminergic neural pathways on the hypothalamic control of feeding behaviour in ruminants. In the first experiment, the animals were injected (1 microL) with a physiological Tyrode (0.95%) solution, muscimol (0.5 and 1.0 nmol), GABA (0.5 and 1.0 nmol), and L-glutamic acid (0.5 and 1.0 nmol). Feed intake following injections of muscimol (1.0 nmol) and L-glutamic acid (0.5 and 1.0 nmol) was twice as large as that following the Tyrode solution, at 60-min postinjections. These results, however, were not statistically significant (p = 0.12-0.15). In the second experiment, the animals were injected (1 microL) with saline, muscimol (0.8 nmol), L-glutamic acid (0.8 nmol), and pentobarbital (0.26 mumol). Fifteen minutes after the injections, pentobarbital had induced a significant feeding response when compared with control values (p less than 0.01), whereas the effect of L-glutamic acid was not significant. However, 30 min after the injections, feed intake of sheep having received L-glutamic acid was higher than that obtained with the control injections (p less than 0.01). The response to pentobarbital was stronger than that to either muscimol or L-glutamic acid. Histological analyses of brain tissue indicated that injections were performed in the ventromedial hypothalamus of four sheep and in the dorsomedial hypothalamus of the other. The data indicate that L-glutamic acid stimulates feed intake by acting either as a precursor of GABA or by a direct stimulation of glutaminergic neural pathways involved in the control of feed intake.

Animals↗
PubMed1971

The urinary excretion of orally administered pteroyl-L-glutamic acid by the rat.

1. The urinary excretion of folates after oral administration of [2-(14)C]pteroyl-l-glutamic acid was studied by assaying the radioactivity in the urine and in materials purified and characterized by t.l.c. 2. Radioactivity excreted was 6.8, 5.9 and 30.7% of the oral dose in the first 24h after doses of 3.1, 32 and 320mug/kg respectively. 3. Extensive decomposition of urinary folates to pteroyl-l-glutamic acid was prevented by antioxidants or collection of urine frozen. 4. At the three dosages, two major and one minor radioactive compounds were isolated. One of the major metabolites was 5-methyltetrahydropteroylglutamic acid. The others were unidentified but were not pteroylglutamic acid, 7,8-dihydro-, 5,6,7,8-tetrahydro-, 5- or 10-formyl-tetrahydro-, 5,10-methylidyne-tetrahydro-, 5-formimidoyl-tetrahydro-, 5,10-methylene-tetrahydro-, 5-methyltetrahydro-pteroylglutamic acid, nor any decomposition products of these compounds formed during isolation. Labelled unconjugated pteridines were absent. 5. Labelled pteroyl-l-glutamic acid was displaced by oral administration of unlabelled pteroyl-l-glutamic acid (1.6mg/kg) when given 3.5h after, but not when given 24h after the labelled dose. 6. The results show that orally administered [2-(14)C]pteroyl-l-glutamic acid is absorbed without metabolism and is then metabolized into naturally occurring tetrahydro-folates. 7. These findings are discussed with reference to previous work.

Administration, Oral↗
PubMed1989

Uptake of glutamic acid by Streptococcus salivarius subsp. thermophilus CNRZ 302.

Glutamic acid uptake in Streptococcus salivarius subsp. thermophilus was energy dependent, the source of energy and adaptation to sugar being important to efficiency of uptake. The disaccharides, lactose and sucrose, stimulated uptake, but cells grown in glucose were more active. Optimum temperature was approximately 40 degrees C and pH approximately 7.0. NaCl was strongly inhibitory to the uptake of glutamic acid although not to that of isoleucine. High specificity existed because only L-aspartic acid was inhibitory.

Disaccharides↗
PubMed1992

Improved biocompatibility of bioprosthetic heart valves by L-glutamic acid treatment.

Treatment of glutaraldehyde-fixed pericardium with L-glutamic acid and storage in bacteriostatic preservatives (paraben) stably antagonizes free, reactive aldehyde groups within the fixed bioprosthetic heart valve tissue. In 63-day subcutaneous implants in rats, the calcification rate of this treatment (13.3 +/- 2 mg calcium/g wt tissue) was markedly reduced as compared to conventionally treated tissue (169 +/- 24 mg/g; p less than 0.05). To test the influence of tissue-released toxic aldehydes on spontaneous endothelial cell ingrowth in vivo, vascular grafts (8-cm long, 6-mm diameter) from fixed pericardium treated with L-glutamic acid were interposed into the carotid arteries in ten sheep. They were compared to grafts from conventionally treated pericardium implanted at the contralateral side. Following 3 months of implantation, planimetry revealed 49% +/- 20% of the surface of conventionally preserved pericardium to be covered with red thrombus, but only 12% +/- 5% in L-glutamic acid treated pericardium (p less than 0.05). The ultrastructural findings of a closed endothelial cell layer on the graft surface reveals the new technique to be a promising approach towards increased biocompatibility of aldehyde-fixed bioprosthetic heart valves.

Animals↗
PubMed1998

Mechanism of the inhibitory effect of imipramine on the Na+-dependent transport of L-glutamic acid in rat intestinal brush-border membrane.

The mechanism of the inhibitory effect of imipramine, a lipophilic organic cation on the Na+-dependent transport of L-glutamic acid across intestinal brush-border membrane was investigated. The uptake of L-glutamic acid by intestinal brush-border membrane vesicles was dependent on the concentration of Na+. Fitting of the uptake data in the presence of various concentrations of Na+ using Hill equation yielded a Hill coefficient of 2.18. This result suggest that the carrier system of L-glutamic acid has at least two sites for Na+-binding. By the analysis of double reciprocal plot and Dixon-type plot, it was found that imipramine inhibits the transport of L-glutamic acid by interacting competitively with the binding sites of Na+, but not inhibit L-glutamic acid binding site. Moreover, the effect of imipramine on the transport of L-alanine and D-glucose which are co-transported with only one Na+ molecule was also suggestive of interaction with the Na+-binding sites on the carrier. These results indicate that the mechanism of the inhibitory effect of imipramine on the Na+-dependent carrier systems is common for all systems regardless of the stoichiometry or substrates.

Alanine↗
PubMed2005

Synthesis of 10- and 9-membered dilactams derived from aspartic and glutamic acids.

9- and 10-membered bridged dipeptides derived from L-aspartic acid and L- or D-glutamic acid were synthesized using aminoacyl incorporation reaction. Key intermediates containing internal pyroglutamyl moiety were prepared via side chain to backbone cyclization of related protected dipeptide derivatives of glutamic acid.

Aspartic Acid↗
PubMedDate not supplied

Glutamine or glutamic acid effects on intestinal growth and disaccharidase activity in infant piglets receiving total parenteral nutrition.

This study was designed to measure the effect of free glutamine or glutamic acid supplementation on small intestinal growth and disaccharidase enzyme activity in 7-day-old miniature piglets. The piglets received one of three total parenteral nutrition solutions exclusively for 7 days. All three solutions were isonitrogenous and isocaloric, and glutamine or glutamic acid was included at physiological levels (5% of the total amino acid content) in two of the three solutions; the third (control) contained neither glutamine nor glutamic acid. No differences were seen between groups in plasma glutamine or glutamic acid concentrations. Similarly, no effect was observed on small intestinal protein or DNA content or on the specific activities of lactase, sucrase, or maltase. These data demonstrate that in the healthy miniature piglet, parenteral glutamine or glutamic acid supplemented at physiological doses does not influence small intestinal growth and development.

Animals↗
PubMed2001

G76E substitution in type I collagen is the first nonlethal glutamic acid substitution in the alpha1(I) chain and alters folding of the N-terminal end of the helix.

The majority of osteogenesis imperfecta (OI) is caused by substitutions for glycine residues in the two alpha chains of type I collagen. Since only 4% of possible nucleotide changes in type I collagen glycine codons would result in a glutamic acid substitution, these are predicted to be infrequent. Only one glutamic acid substitution in type I collagen has been fully reported. We describe here the clinical, biochemical, and molecular characterization of a girl with severe type III OI caused by a G76E substitution in COL1A1. This is the first delineation of a glutamic acid substitution in the alpha1(I) chain causing nonlethal osteogenesis imperfecta. The proband's fibroblast type I collagen chains and cyanogen bromide peptides were electrophoretically normal, while osteoblast collagen was slightly overmodified. This suggested a mutation near the N-terminal end of the collagen helix. A mismatch was detected by RNA:DNA hybrid analysis in cDNA coding for 106 amino acids at the N-terminal end of the helical region. Subclones of both alleles were sequenced and revealed a G --> A (c.761G > A) mutation causing an alpha1(I) G76E substitution in one allele. The presence of the mutation in the proband's leukocyte gDNA, and its absence in parental gDNA, was confirmed by Tsp509I digestion. The glutamic acid substitution alters the folding of the mutant collagen helices. Pericellular processing of type I collagen by the proband's fibroblasts yielded an earlier appearance of the pC-alpha1(I) form and of mature alpha chains as compared to control cell processing. Also, the presence of the glutamic acid substitution apparently exposes the adjacent Arg75 residue in the alpha1 chain. Trypsin digestion of proband fibroblast collagen resulted in shortened alpha1 chains, as confirmed by CNBr analysis. In addition, the Tm for mutant helices from fibroblasts and osteoblasts was decreased 2-4 degrees C versus controls, demonstrating a decrease in helix stability. These findings increase our understanding of the disruptive effect of glutamic acid substitutions in collagen.

Adolescent↗
PubMed2004

Time-resolved photointermediate changes in rhodopsin glutamic acid 181 mutants.

The role of glutamic acid 181 in the bovine rhodopsin retinylidene chromophore pocket was studied by expressing E181 mutants in COS cells and measuring, as a function of time, the absorbance changes produced after excitation of lauryl maltoside pigment suspensions with 7 ns laser pulses. All mutants studied except E181D showed accelerated decay of bathorhodopsin compared to wild type. Even for E181D, an anomalously large blue shift was observed in the absorption spectrum of the bathorhodopsin decay product, BSI. These observations support the idea that E181 plays a significant role in the earliest stages of receptor activation. E181 mutations have a pronounced effect on the decay of the lumirhodopsin photointermediate, primarily affecting the size of the red shift that occurs in the lumirhodopsin I to lumirhodopsin II transition that takes place on the 10 micros time scale after wild-type photoexcitation. While the spectral change that occurs in the lumirhodopsin I to lumirhodopsin II transition in wild-type rhodopsin is very small ( approximately 2 nm), making it difficult to detect, it is larger in E181D ( approximately 6 nm), making it evident even in the lower signal-to-noise ratio measurements possible with rhodopsin mutants. The change seen is even larger for the E181F mutant where significant amounts of a deprotonated Schiff base intermediate are produced with the 10 micros time constant of lumirhodopsin II formation. The E181Q mutant shows lumirhodopsin decay more similar to wild-type behavior, and no lumirhodopsin I to lumirhodopsin II transition can be resolved. The addition of chloride ion to E181Q increases the lumirhodopsin I-lumirhodopsin II spectral shift and slows the deprotonation of the Schiff base. The latter result is consistent with the idea that a negative charge at position 181 contributes to protonated Schiff base stability in the later intermediates.

Amino Acid Substitution↗
PubMed1995

Attenuation of morphine-induced antinociception by L-glutamic acid at the spinal site in rats.

The present experimental study was planned to evaluate the effect of intrathecal administration of L-glutamic acid upon antinociception produced by intrathecal morphine in a prospective-controlled manner in conscious freely mobile Sprague-Dawley albino rats. After chronic catheterization of the spinal subarachnoid space, rats were randomly allocated into 12 treatment groups of ten each and the same number of rats served as saline control for the comparison. L-glutamic acid (100 mmol), morphine (1.2 mmol), ketamine (50 mmol) and saline (150 mmol) were injected intrathecally in 5 microliters volumes. Naloxone was injected in a dose of 1 mg.kg-1 im. Immediately before and 15, 30 min, 1, 2 and 3 hr after injection, rats were subjected to a thermal noxious stimulus, using a tail-flick technoanalgesiometer and tail-flick latencies (TFL) were recorded. Intrathecal administration of L-glutamic acid attenuated the antinociceptive effect of intrathecal morphine with a decrease in TFL (1.4 +/- 0.3 sec; P < 0.0001) from 6.6 +/- 0.3 sec. Ketamine led to abolition of this effect (P < 0.01). In rats, pretreated with naloxone, there was restoration as well as augmentation of morphine-induced antinociception in the presence of L-glutamic acid with an increase in TFL (9.0 +/- 0.4 sec; P < 0.0001). We conclude that there is modulation of opioid receptors by L-glutamic acid at the spinal site in rats.

Analgesia↗
PubMed2001

[Effects of metal ions on gamma-poly (glutamic acid) synthesis by Bacillus licheniformis].

In the course of gamma-poly (glutamic acid) gamma-PGA fermentation, metal ions K+, Mg2+, Fe3+, Ca2+, Mo6+, Mn2+, Co2+ and Zn2+ in the medium have certain effects on the synthesis of gamma-poly(glutamic acid). Excess or lack of K+, Mg2+ and Fe3+ results in reduced yield of gamma-PGA. It was found that the gamma-PGA synthesis by Bacillus licheniformis was promoted obviously by Ca2+ and Mo6+. Synthesis and stereochemical composition of gamma-PGA was greatly regulated by Mn2+. gamma-PGA was not produced without Mn2+ in medium, and with the increase of Zn2+ concentration the yield of gamma-PGA and the proportion of D-glutamic acid in the peptide increase. Regulative effect of Co2+ and Zn2+ was almost the same as that of Mn2+, thus the combination of Mn2+, Co2+ cannot enhance gamma-PGA synthesis and affect stereochemical composition of gamma-PGA. Based on the experimental date, an appropriate formulation of metal ions in the medium for gamma-PGA production was obtained.

Bacillus↗
PubMed1983

Glutamic acid is an active site residue of angiotensin I-converting enzyme. Use of the Lossen rearrangement for identification of dicarboxylic acid residues.

A set of chemical reactions was used to show that one glutamic acid residue at the active site of bovine lung angiotensin I-converting enzyme is esterified with the alkylating agent p-[N,N-bis(chloroethyl)amino] phenylbutyryl-L-Pro (chlorambucyl-L-Pro), an affinity label for this enzyme (Harris, R. B., and Wilson, I. B. (1982) J. Biol. Chem. 257, 811-815). The same procedure was used to confirm that a glutamic acid residue of carboxypeptidase A alpha is esterified by reaction with bromoacetyl-N-methyl-L-phenylalanine (Haas, G. M., and Neurath, H. (1971) Biochemistry 10, 3535-3546). In the procedure described in this paper, the esterified residue at the active site is converted to the hydroxamic acid by reaction with hydroxylamine and the hydroxamic acid is subject to the Lossen rearrangement. If a glutamic acid residue was esterified, 1 eq of 2,4-diaminobutyric acid will be formed. Aspartyl esters will give 2,3-diaminopropionic acid. The diamino acids can be quantitatively measured using the short column of an amino acid analyzer if the amount of lysine and histidine is largely decreased by modification with suitable side chain protecting groups. With carboxypeptidase A, the reactions were done on the whole undigested enzyme. With the converting enzyme, we first cleaved the esterified enzyme with cyanogen bromide. Twenty-nine cleavage peptides were separated on high performance liquid chromatography and one of these contained all of the bound radioactive inhibitor. This active site peptide was then subjected to the derivatization and Lossen procedures, and 1 eq of 2,4-diaminobutyric acid was obtained.

Amino Acids↗