L-glutamine Acid Research Articles

Determination of L-Cystine in Tablets Using the Chemiluminescence Method

Aim. To develop the method for the quantitative determination of L-cystine in sublingual tablets Elthacin ® using the method of chemiluminescence inhibition in the H 2 L (luminol) – Н 2 О 2 – Нb (hemoglobin) system. Materials and methods. The study objects were the pure substance of L-cystine of pharmaceutical grade and sublingual tablets Elthacin ® produced by the Medical Scientific-Production Complex “Biotics Ltd” (Russia) containing 70 mg of glycine, L-glutaminic acid and L-cystine in their composition. The intensity of chemiluminescence was measured on the device with a FEU-84-A photoelectric multiplier using an IMT-0.5 measuring instrument of low currents and a quick-acting automatic potentiometer. Results and discussion. The method of the L-cystine quantitative determination in tablets based on the inhibition of chemiluminescence in the H 2 L – H 2 O 2 – Hb system has been developed. The calibration graph was linear over the concentration range from 7 to 70 μg · mL –1 . No interferences were observed in the presence of common components of the tablets, such as glycine and L-glutaminic acid. RSD = ± 2.35 %, (δ = + 1.13 %), LOD (3S) = 4 μg · mL –1 , LOQ (10S) = 13 μg · mL –1 for the sublingual tablets Elthacin ® . Conclusions. The method proposed is promising for further research on the subject of its application for the determination of L-cystine in drugs.

Interplay between composition, structural dynamics and thermodynamic data in amino acid nitrates

A systematic thermodynamic study has been performed for a series of nitrates having cations derived from the α-amino acids glycine (Gly), l-proline (Pro) and l-glutamine (Gln). Combustion and formation enthalpies were for the first time obtained for these amino acid nitrates (AANO3) by using combustion calorimetry. The thermal behavior in the dynamic regime was investigated by DSC measurements. The values of the formation enthalpies for nitrates were compared with those of the corresponding amino acids and discussed in correlation with structural information obtained from spectral data. FTIR and Raman techniques were used to identify functional groups and hydrogen bonds. Large transmittance in the visible region and the band gap energy value obtained from UV–Vis spectra suggest that these materials are suitable for optoelectronic applications. The band gap values are increasing in the order GlyNO3 < ProNO3 < GlnNO3. Additional polarimetric measurements confirmed the chiral nature of ProNO3 and GlnNO3.

Non-target metabolomics pfofiling of neuromyelities optica spectrum disorder

Objective To investigate the metabolomics characteristic of neuromyelities optica spectrum disorder (NMOSD) in plasma and cerebrospinal fluid. Methods Ultra high performance liquid chromatography-mass spectrometry (UHPLC-MS) was used to identify plasma metabolites in 16 patients with NMOSD and 8 healthy controls. At the same time, the identification of metabolites in cerebrospinal fluid of 8 NMOSD patients and 5 healthy controls was completed. Differential metabolites screening and metabolomic pathway analysis were performed by diversified data analysis methods. Results Compared with healthy control group, the content of 8 substances such as Cis.8.11.14.Eicosatrienoic acid in the plasma of NMOSD patients was increased.The content of 8 substances such as L-glutamine acid were decreased. There was no significant difference in the metabolites between Aquaporin 4 (AQP-4) antibody positive and negative NMOSD plasma. The content of 6 substances such as 3-hydroxybutyric acid in cerebrospinal fluid of patients with NMOSD was reduced. Conclusions The distribution of metabolites in plasma between NMOSD patients and healthy controls was significantly different. There was no significant difference in metabolites between AQP-4 antibody positive and negative NMOSD plasma. There are some differences in metabolites between cerebrospinal fluid of NMOSD patients and healthy controls. A variety of amino acid abnormalities, sphingomyelin dysfunction, energy metabolism and mitochondrial dysfunction were involved in the pathogenesis of NMOSD. Key words: Neuromyelitis optica/BL/CF; Chromatography, high pressure liquid; Mass spectrometry; Metabolomics

Molar heat capacity and thermodynamic properties of Lu(C5H9NO4)(C3H4N2)6(ClO4)3·5HClO4·10H2O

A complex of Lutetium perchloric acid coordinated with l-glutaminic acid (C5H9NO4) and imidazole (C3H4N2), Lu(C5H9NO4)(C3H4N2)(6)(ClO4)(3)center dot 5HClO(4)center dot 10H(2)O was synthesized and characterized. Thermodynamic properties of the complex were studied with an adiabatic calorimeter (AC) from 80 to 390 K and differential scanning calorimetry (DSC) from 100 to 300 K. Two thermal abnormalities were discovered at 220.34 and 248.47 K, which were deduced to be phase transitions. One was interpreted as a freezing-in phenomenon of the reorientational motion of ClO4 (-) ions and the other was attributed to the orientational order/disorder process of ClO4 (-) ions. The low-temperature molar heat capacities were measured by AC and the thermodynamic functions [H (T) - H (298.15)] and [S (T) - S (298.15)] were derived in the temperature range from 80 to 390 K with temperature interval of 5 K. Thermal decomposition behavior of the complex was studied by thermogravimetric analysis and DSC.

Biochemical and Immunological Study on the Effects of Barley and its Components as Hypoglycemic Agents in Diabetic Rats

The present study was carried out to investigate the hypoglycemic effect of barley (Hordeum vulgare L) and some of its components such as amino acids (L-leucine and L-glutamine) and chromium picolinate on some biochemical and immunological parameters of alloxan induced diabetic rats. Alloxan-diabetic rats were treated with barley water (10% w/v) at a dose 10 ml Kg -1 b.wt., chromium picolinate at 15 μg Kg -1 b.wt., L-leucine plus L-glutamine at 4.5 mg & 15 mg Kg -1 b.wt., and/or the combination of barley plus chromium plus L-leucine and L-glutamine at the same previous doses in the same water volume, respectively. Rats received the treatments in their drinking water for four weeks. The levels of glucose, immunoglobulin G (IgG), total lipids (TL), cholesterol, triglycerides (TG), low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were significantly (P<0.05) increased, while high-density lipoprotein (HDL) decreased in plasma of alloxan-diabetic rats compared to control group. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), acid phosphatase (AcP) and alkaline phosphatase (AlP) were significantly (P<0.05) decreased in both plasma and liver of alloxan-diabetic rats. On the other hand, the activity of lactate dehydrogenase (LDH) decreased in plasma and increased in liver of alloxan- diabetic rats. Treatment of the diabetic rats with repeated doses of any one of the three treatments alone could restore the changes of the above parameters to their normal levels after four weeks of treatment. However, treatment with the combination of all together did not show complete restoration. Furthermore, the electron microscope results were supported biochemical and immunological findings. The present results showed that barley, amino acids and chromium picolinate exerted antihyperglycemic effects and consequently may alleviate liver damage caused by alloxan-induced diabetes.

Synthesis of Amino Acid Conjugates and Further Derivatives of 3α-Hydroxylup-20(29)ene-23,28-dioic acid

Triterpenes of betulinic acid type exhibit many interesting biological activities. Therefore a series of new 3α-hydroxy-lup-20(29)-ene-23,28-dioic acid derivatives 2a—22 with putative pharmacological activities were synthesized. As starting compounds 3α-hydroxy-lup-20(29)-ene-23,28-dioic acid (1a), isolated from Schefflera octophylla, or its 3-O-acetyl derivative 1b were used. Mono- and diesters (2a—b from 1a, and 4d from 4c) were prepared with CH2N2. Oxidation of the isopropenyl side chain with OsO4 yielded the 20,29-diols (4a—b from 1b, and 19 from 17), which were in the case of 4b further transformed to the 29-norketones 8a/mdash;b. Oxidation of the isopropenyl side chain with m-chloroperbenzoic acid afforded the 20,29-epoxide 12 (from 1b) and the 29-aldehydes and a-hydroxy aldehydes (13a—c from 2a, 14a—c from 2b, and 16a—c from 15a). Ring A was modified by a tosylation—elimination sequence using p-TsCl/NaOAc, which afforded diolefin 15a (from 2a) with Δ2,20(29) double bonds or 23-nor-Δ3,20(29)diolefin 17 (from 1a). Compounds 4b, 4c, and 8a were coupled with L-methionin, L-phenylalanin, L-alanin, L-serin, and L-glutaminic acid via amide bonds at positions 23 and 28 to afford the amino acid conjugates 5a—7b and 9a—11.

Effects of L-glutamyl peptides on the growth of L-glutamic acid crystals (α-form)

The effects of five γ-L-glutamyl peptides, two α-L-glutamyl peptides, and L-phenylalanine (L-Phe) on the growth of {111} and {001} faces of the α-form of L-glutaminic acid (L-Glu) crystals were investigated. All the γ-L-glutamyl and α-L-glutamyl peptides and L-Phe had inhibitory effects on the growth of the {111} face, but γ-Glu-Glu, γ-Glu-ϵ-Lys, and Glu-Glu suppressed not only the {111} faces but also the {001} faces. Thus, the distribution of additives on the {111} and {001} faces of L-Glu crystals was analyzed. Results showed that the {001} face of L-Glu crystals had higher concentrations of γ-Glu-Glu, γ-Glu-ϵ-Lys, and Glu-Glu than other peptides. The effect of γ-Glu-Glu on inducing the β-form is considered to be closely related to its specific character of inhibiting the growth of both the {111} and {001} faces of the α-form. These phenomena are discussed on the basis of the crystal structure.

Isolation by anion-exchange of immunologically and enzymatically active human islet glutamic acid decarboxylase 65 overexpressed in Sf9 insect cells

The enzyme L-glutamic acid decarboxylase is a major autoantigen of the beta cell. Autoantibodies against this enzyme are observed before the onset of insulin-dependent diabetes mellitus (IDDM) in man and may be of predictive value. There is evidence that this enzyme is involved in the development of autoimmune diabetes in animals. In order to facilitate the investigation of the role of L-glutamine acid decarboxylase in IDDM, we expressed the 65 kDa isoform of human islet L-glutamic acid decarboxylase in insect cells using a baculovirus-based vector. The material was expressed at high levels (up to 50 mg/l of cells). Partially purified metabolically labelled L-glutamic acid decarboxylase bound to immunoglobulins in the sera from 20 of 49 subjects with newly-diagnosed IDDM. The enzyme was isolated in high yields (up to 26 mg/l cell culture) with fully maintained enzymatic activity by either ion-exchange chromatography or immunoaffinity chromatography. Purified L-glutamic acid decarboxylase inhibited the binding of radioactive L-glutamic acid decarboxylase, prepared by in vitro translation of mRNA, to immunoglobulins in the sera of subjects with IDDM. Recombinant human islet L-glutamic acid decarboxylase, isolated from Sf9 cells, is a suitable material for the large scale investigation of the utility of this enzyme in the prediction and prevention of autoimmune diabetes.

Taenia crassiceps: Temperature, polycations, polyanions, and cysticercal endocytosis

The effect of various temperatures, poly- l-lysine, and poly- l-glutamic acid on endocytosis of smooth micropinocytotic vesicles (pinosomes) in the tegument of the cysticercus of Taenia crassiceps has been investigated stereologically. The temperature regimes used were 0, 5, 10, 20, 30, and 40 C. Maximum volume, surface density, and number per unit volume were found at 40 C, and minimum surface-to-volume ratio and numbers at 10 C. At 10 C, mean pinosome volume and mean surface area per pinosome were maximal, but volume and surface density did not differ significantly from 40 C. It is proposed that this anomalous finding for 10 C incubations was due to this being a critical temperature at which a slower rate of pinosome formation was compensated for by the formation of larger individual pinosomes. Poly- l-lysine was shown to be a stimulant of pinosome formation, leading to a significant increase in numbers per unit volume. However, volume and surface density, surface-to-volume ratio, mean volume, and mean surface area per pinosome were not significantly different in poly- l-lysine-incubated samples, when compared to controls (fresh from the mouse) or incubations in medium only or samples returned to medium after poly- l-lysine incubation, the only exception being surface to volume ratio and mean volume of pinosomes in the 75-min incubation. These anomalous results were explained by a marked reduction in the form ellipse values, which indicated the production of more elliptical-shaped pinosomes under poly- l-lysine stimulation. Incubation in poly- l-glutamine acid did not have any significant effect at any incubation time.

Characteristics of a cationic amino acid transport system in the basolateral membrane of the cat salivary epithelium.

The specificity and kinetics of L-lysine influx across the basolateral surface of the cat salivary epithelium have been investigated in the perfused cat submandibular gland using a high-resolution, paired-tracer dilution technique. L-lysine influx was measured at several different perfusate concentrations (0.05-2.5 mM) and was found to be saturable. A Michaelis-Menten analysis based on a single entry site gave a Km of 0.49 +/- 0.08 mM and a Vmax of 231 +/- 20 nmol/min X g. The uptake of L-lysine was highly stereospecific and markedly inhibited by L-arginine (0.25-2.5 mM). The inhibitor constant (Ki) was 0.23 mM, suggesting that the carrier had a greater affinity for L-arginine than L-lysine. When the inhibitory effects of L-histidine (0.5-10 mM) were examined the Ki, estimated at 10 mM, was 4.6 mM. Nine other neutral amino acids (L-alanine, L-serine, L-cysteine, glycine, L-proline, L-homoserine, L-leucine, L-phenylalanine and L-glutamine), and an acidic amino acid (L-aspartate) were also tested at 10 mM and, although several caused inhibition, the Ki was always at least 20 times higher than the measured Km for L-lysine. It is concluded the carrier is highly specific for the L-form of the basic amino acids. The sodium dependence of L-lysine influx was investigated over a range of L-lysine concentrations (0.05-1 mM), and total removal of sodium from the perfusate had no effect on L-lysine influx. In the presence of sodium, L-homoserine, an amino acid not normally present in animal tissues, inhibited L-lysine influx (Ki = 13 mM). This inhibition was not observed in the absence of sodium, and contrasts with the observation that the inhibitory action of L-histidine was sodium independent. The present data suggest that a specific cationic amino acid transport system is operative in the basolateral membrane of the cat salivary epithelium. The properties of this system appear to be similar to the system y+ which has been described in several other cell types.

Release of [ 3H] l-glutamine acid ( l-Glu) and [ 3H] d-aspartic acid ( d-Asp) in the area of nucleus tractus solitarius in vivo produced by stimulation of the vagus nerve

We have investigated the effects of bilateral electrical stimulation of the vagus nerves in anesthetized, paralyzed rats on the release of exogenously administered [ 3H] l-glutamic acid ([ 3H] l-Glu) or [ 3H] d-aspartic acid ([ 3H] d-Asp) from the intermediate portion of the nucleus tractus solitarius (NTS). Electrical stimulation of afferent fibers with the frequency, pulse, duration, and intensity required to activate C-fibers, elicted hypotension and bradycardia. Such stimuli induced the release of [ 3H] l-Glu, or its stable analogue [ 3H] d-Asp, from the NTS into perfusate collected through push-pull cannulae. The release of radioactive materials, calculated as a percent of increase in radioactivity above the prestimulation level, was for [ 3H] l-Glu 114.4 ± 25.1% (n= 20) during bilateral vagal stimulation, and45.6 ± 11.3% (n= 9) (P < 0.001) during unilateral stimulation. The release of [ 3H] d-Asp induced by bilateral vagal stimulation was100.4 ± 31.9%. The release, which was anatomically specific and restricted to the NTS, was directly related to stimulus (and hence reflex) intensity. Overflow of the inert substances [ 14C]urea or [ 14C]sucrose, co-administered with the [ 3H]amino acids, did not increase at the same time. Local depolarization of the cells in the NTS by K + (53 mM) increased the overflow of [ 3H] l-Glu, as well as [ 14C]urea, and was able to induce the release of [ 3H] l-Glu when electrical stimulation failed to have an effect. The results are consistent with the hypothesis that l-Glu is a neurotransmitter of neurons in the NTS mediating vasodepressor response from vagal afferents, including those from systemic baroreceptors.

Untersuchungen zum Enzymspektrum von Erysipelothrix rhusiopathiae

The enzyme spectrum of non proliferating cells of Erysipelothrix rhusiopathiae was investigated by means of different low molecular synthetic substrates. Activities of aminopeptidases were found directed against compounds of L-alanine, L-arginine, L-aspartic acid, glycine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-tryptophane, and L-tyrosine, but not against compounds of L-cystine, L-glutaminic acid, L-histidine, L-hydroxyproline, and L-valine (Table 1). The pH optimum of the investigated aminopeptidases ranges from neutral to alcaline reaction (Table 2). Trypsine, chymotrypsine, or chymotrypsine-like proteases were not detected. E. rhusiopathiae possess esterase activity splitting esters of lower carboxylic acids, i. e. acetic acid, propionic acid, butyric acid, caproic acid, and caprylic acid, but no lipase activity. Under the proved glycosidases only α- and β-D-galactosidase and glucosaminidase were positive. Weak activities of phosphatases and arylsulfatase were found also (Table 3).

Enzymatic profile of Legionella pneumophilia.

The enzyme activities of four strains of Legionella pneumophilia were investigated by using the API ZYM system (API System S.A., F-38390 Montalieu Vercieu, France) and synthetic substrates. Aminopeptidases were detected specifically against L-alanine, L-arginine, L-aspartic acid, L-cystine, L-glutaminic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-tryptophan, L-tyrosine, and L-valine. Furthermore, the bacteria possesses esterase activity splitting propionate, butyrate, caproate, caprylate, and caprate, but not laurate, myristate, palmitate, and stearate, esters. The enzymes studies were inhibited partially by aprotinin. No inhibition of phosphatase (pH range, 5.4 to 8.5) or of phosphoamidase was observed. Activities of arylsulfatase, chymotrypsin, trypsin, and glycosidases could not be detected.

Effects of L-glutamic acid and kainic acid on central cardiovascular control

L-Glutamine acid and kainic acid injected int o the cisterna magna of dogs, produced a dose-dependent increase in blood pressure and a decrease in heart rate. In contrast, intravenous injection of both compounds was ineeffective. The hypertension was probably due to an increase in sympathetic tone as guanethidine prevented the rise in blood pressure induced by central administration of L-glutamic acid and kainic acid. Kainic acid was 1000 fold more potent than L-glutamic acid.

Phenotypic reversion of nitrogenase in pleiotropic mutants of Rhizobium meliloti

In two out of three pleiotropic mutants of Rhizobium meliloti, defective in nitrate reductase induced by amino acid utilization in vegetative bacteria and in symbiotic nitrogen fixation, nitrogenase activity could be restored completely by purines and partially by the amino acids L-glutamate, L-aspartate, L-glutamine, and L-asparagine. The compounds restoring effectiveness in nitrogen fixation did not restore nitrate reductase activity in vegetative bacteria. The restoration of effectiveness supports our earlier conclusion that the mutation is not in the structural gene for a suggested common subunit of nitrogenase and nitrate reductase.