Check out our New Publishers' Select for Free Articles

Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.33, #4)

Effects of amino acid-derived luminal metabolites on the colonic epithelium and physiopathological consequences by F. Blachier; F. Mariotti; J. F. Huneau; D. Tomé (pp. 547-562).

Depending on the amount of alimentary proteins, between 6 and 18 g nitrogenous material per day enter the large intestine lumen through the ileocaecal junction. This material is used as substrates by the flora resulting eventually in the presence of a complex mixture of metabolites including ammonia, hydrogen sulfide, short and branched-chain fatty acids, amines; phenolic, indolic and N-nitroso compounds. The beneficial versus deleterious effects of these compounds on the colonic epithelium depend on parameters such as their luminal concentrations, the duration of the colonic stasis, the detoxication capacity of epithelial cells in response to increase of metabolite concentrations, the cellular metabolic utilization of these metabolites as well as their effects on colonocyte intermediary and oxidative metabolism. Furthermore, the effects of metabolites on electrolyte movements through the colonic epithelium must as well be taken into consideration for such an evaluation. The situation is further complicated by the fact that other non-nitrogenous compounds are believed to interfere with these various phenomenons. Finally, the pathological consequences of the presence of excessive concentrations of these compounds are related to the short- and, most important, long-term effects of these compounds on the rapid colonic epithelium renewing and homeostasis.

Keywords: Keywords: Amino acids – Bacterial metabolites – Colon epithelium – Adaptative metabolism

D-serine: a new word in the glutamatergic neuro-glial language by M. J. Scolari; G. B. Acosta (pp. 563-574).

Gliotransmission is a process in which astrocytes are dynamic elements that influence synaptic transmission and synaptogenesis. The best-known gliotransmitters are glutamate and ATP. However, in the past decade, it has been demonstrated that D-serine, a D-amino acid, acts as a gliotransmitter in glutamatergic synapses. The physiological relevance of D-serine is sustained by the way in which it modulates the action of glutamatergic neurotransmission, neuronal migration and long-term potentiation (LTP). In addition, the synthesis and degradation mechanisms of D-serine have been proposed as potential therapeutic targets for the treatment of Alzheimer’s disease, schizophrenia and related disorders. In the present review, detailed information is provided about the physiological and physiopathological relevance of D-serine, including metabolic and regulation aspects.

Keywords: Keywords: Gliotransmission – D-serine – Glutamate – NMDA – Glycine site

Cytoplasmic/nuclear localization of tuberin in different cell lines by M. Rosner; M. Hengstschläger (pp. 575-579).

Tuberous sclerosis (TSC) is an autosomal dominantly inherited disease affecting 1 in 6000 individuals. The TSC gene products, hamartin and tuberin, form a complex, of which tuberin is assumed to be the functional component being involved in a wide variety of different cellular processes. Tuberin has been demonstrated to be localized to both, the cytoplasm and the nucleus. The cytoplasmic/nuclear localization of tuberin is known to be regulated by the serine/threonine protein kinase Akt. Akt also regulates the cytoplasmic/nuclear localization of the cyclin-dependent kinase inhibitor p27. In this study the localization of these two Akt-regulated proteins was analysed in different cell lines.

Keywords: Keywords: Tuberin – p27 – Localization – Nucleus – Cytoplasm

The effect of taurine on polymorphonuclear leukocyte functions in endotoxemia by H. Erdamar; N. Türközkan; M. Ekremoğlu; Y. Kurt; H. Yaman (pp. 581-585).

The aim of the present study was to measure MPO activity in PMN leukocytes after endotoxin administration, and to compare the levels of NO₂ ⁻ competing with taurine for reaction with HOCl. Furthermore we aimed to determine TauCl levels, a product of MPO–H₂O₂–Halide system, and to evaluate anti-inflammatory properties of PMN in endotoxemia. In addition, our second objective was to investigate the effect of taurine, an antioxidant amino acid, on anti-bactericidal and anti-inflammatory functions of PMN after administration of endotoxin together with taurine.All experiments were performed with four groups (control, taurine, endotoxemia, and taurine plus endotoxin) of ten guinea pigs. After endotoxin administration (4 mg/kg), MPO activities increased and taurine levels decreased. Therefore levels of TauCl, NO₂ ^•− increased. We observed the effects of taurine as conflicting. When taurine was administrated alone (300 mg/kg), all of these parameters decreased.Consequently, we suggested that taurine is influential in infected subjects but not on healthy ones as an antioxidative amino acid. In addition, we believe that in vivo effects of taurine may differ from those in vitro depending on its dosage.

Keywords: Keywords: Polymorphonuclear leukocyte – Taurine – Myeloperoxidase – Nitric oxide

Biotechnology applications of amino acids in protein purification and formulations by T. Arakawa; K. Tsumoto; Y. Kita; B. Chang; D. Ejima (pp. 587-605).

Amino acids are widely used in biotechnology applications. Since amino acids are natural compounds, they can be safely used in pharmaceutical applications, e.g., as a solvent additive for protein purification and as an excipient for protein formulations. At high concentrations, certain amino acids are found to raise intra-cellular osmotic pressure and adjust to the high salt concentrations of the surrounding medium. They are called “compatible solutes”, since they do not affect macromolecular function. Not only are they needed to increase the osmotic pressure, they are known to increase the stability of the proteins. Sucrose, glycerol and certain amino acids were used to enhance the stability of unstable proteins after isolation from natural environments. The mechanism of the action of these protein-stabilizing amino acids is relatively well understood. On the contrary, arginine was accidentally discovered as a useful reagent for assisting in the refolding of recombinant proteins. This effect of arginine was ascribed to its ability to suppress aggregation of the proteins during refolding, thereby increasing refolding efficiency. By the same mechanism, arginine now finds much wider applications than previously anticipated in the research and development of proteins, in particular in pharmaceutical applications. For example, arginine solubilizes proteins from loose inclusion bodies, resulting in efficient production of active proteins. Arginine suppresses protein–protein interactions in solution and also non-specific adsorption to gel permeation chromatography columns. Arginine facilitates elution of bound proteins from various column resins, including Protein-A or dye affinity columns and hydrophobic interaction columns. This review covers various biotechnology applications of amino acids, in particular arginine.

Keywords: Keywords: Protein purification – Osmolyte – Formulation – Lyophilization – Aggregation suppression

Analysis of methionine oxides and nitrogen-transporting amino acids in chilled and acclimated maize seedlings by A. D. Simonović; M. D. Anderson (pp. 607-613).

In maize seedlings, chilling causes a reduction of glutamine synthetase (GS) activity, while acclimation protects GS (manuscript submitted). Since ROS can oxidize both protein-bound and free Met to methionine sulfoxide (MSO) and further to methionine sulfone (MSO2, a GS inhibitor), it was hypothesized that the chilling-induced oxidative stress may cause accumulation of MSO and MSO2, thus contributing to the inactivation of GS. MSO2 preferentially inhibited the chloroplastic isoform, GS2. HPLC analysis of polar amino acids from coleoptiles + leaves, mesocotyls and roots of control, chilled, acclimated, acclimated and chilled and chilled and rewarmed plants revealed that free MSO and MSO2 do not accumulate after low temperature treatments. Nevertheless, acclimation significantly increased the expression of putative protein methionine sulfoxide reductase (PMSR), especially in mesocotyls. Different low temperature treatments caused complex changes in the profiles of N-transporting amino acids, Asp, Glu, Asn and Gln.

Keywords: Keywords: Glutamine synthetase – Methionine oxides – N-transporting amino acids – Chilling – Acclimation – PMSR

DNA damage during glycation of lysine by methylglyoxal: assessment of vitamins in preventing damage by G. Suji; S. Sivakami (pp. 615-621).

Amino acids react with methylglyoxal to form advanced glycation end products. This reaction is known to produce free radicals. In this study, cleavage to plasmid DNA was induced by the glycation of lysine with methylglyoxal in the presence of iron(III). This system was found to produce superoxide as well as hydroxyl radicals. The abilities of various vitamins to prevent damage to plasmid DNA were evaluated. Pyridoxal-5-phosphate showed maximum protection, while pyridoxamine showed no protection. The protective abilities could be directly correlated to inhibition of production of hydroxyl and superoxide radicals. Pyridoxal-5-phosphate exhibited low radical scavenging ability as evaluated by its TEAC, but showed maximum protection probably by interfering in free radical production. Pyridoxamine did not inhibit free radical production. Thiamine and thiamine pyrophosphate, both showed protective effects albeit to different extents. Tetrahydrofolic acid showed better antioxidant activity than folic acid but was found to damage DNA by itself probably by superoxide generation.

Keywords: Keywords: Advanced glycation end products – Diabetes – DNA – Free radicals – Glycation – Lysine – Methylglyoxal – Vitamins

Using pseudo amino acid composition and binary-tree support vector machines to predict protein structural classes by T.-L. Zhang; Y.-S. Ding (pp. 623-629).

Compared with the conventional amino acid composition (AA), the pseudo amino acid composition (PseAA) as originally introduced by Chou can incorporate much more information of a protein sequence; this remarkably enhances the power to use a discrete model for predicting various attributes of a protein. In this study, based on the concept of Chou’s PseAA, a 46-D (dimensional) PseAA was formulated to represent the sample of a protein and a new approach based on binary-tree support vector machines (BTSVMs) was proposed to predict the protein structural class. BTSVMs algorithm has the capability in solving the problem of unclassifiable data points in multi-class SVMs. The results by both the 10-fold cross-validation and jackknife tests demonstrate that the predictive performance using the new PseAA (46-D) is better than that of AA (20-D), which is widely used in many algorithms for protein structural class prediction. The results obtained by the new approach are quite encouraging, indicating that it can at least play a complimentary role to many of the existing methods and is a useful tool for predicting many other protein attributes as well.

Keywords: Keywords: Protein structure classes – Pseudo amino acid composition – Correlation of amino acid – Hydrophobic amino acid couple – Binary tree support vector machines

The intramolecular δ¹⁵N of lysine responds to respiratory status in Paracoccus denitrificans by B. S. Pan; C. J. Wolyniak; J. T. Brenna (pp. 631-638).

Presented here is the first experimental evidence that natural, intramolecular, isotope ratios are sensitive to physiological status, based on observations of intramolecular δ¹⁵N of lysine in the mitochondrial mimic Paracoccus denitrificans. Paracoccus denitrificans, a versatile, gram-negative bacterium, was grown either aerobically or anaerobically on isotopically-characterized ammonium as sole cell-nitrogen source. Nitrogen isotope composition of the biomass with respect to source ammonium was $Delta^{15}{ m N}_{{ m cell}-{ m NH}_4}={{delta}}^{15}{ m N}_{{ m cell}}-{{delta}}^{15}{ m N}_{{ m NH}_4}$ = −6.2 ± 1.2‰ for whole cells under aerobic respiration, whereas cells grown anaerobically produced no net fractionation ( $Delta^{15}{ m N}_{{ m cell}-{ m NH}_4}$ = −0.3 ± 0.23‰). Fractionation of ¹⁵N between protein nitrogen and total cell nitrogen increased during anaerobic respiration and suggests that residual nitrogen-containing compounds in bacterial cell membranes are isotopically lighter under anaerobic respiration. In aerobic cells, the lysine intramolecular difference between peptide and sidechain nitrogen is negligible, but in anaerobic cells was a remarkable Δ¹⁵N_{p − s} = δ¹⁵N_peptide − δ¹⁵N_sidechain = +11.0‰, driven predominantly by enrichment at the peptide N. Consideration of known lysine pathways suggests this to be likely due to enhanced synthesis of peptidoglycans in the anaerobic state. These data indicate that distinct pathway branching ratios associated with microbial respiration can be detected by natural intramolecular Δδ¹⁵N measurements, and are the first in vivo observations of position-specific measurements of nitrogen isotope fractionation.

Keywords: Keywords: Intramolecular isotope ratio – ¹⁵N/¹⁴N, δ¹⁵N – Paracoccus denitrificans – Nitrogen metabolism

Taurine transporter is expressed in vascular smooth muscle cells by X.-B. Liao; X.-M. Zhou; J.-M. Li; Z.-P. Tan; L.-M. Liu; W. Zhang; H. Tan; Y. Lu; L.-Q. Yuan (pp. 639-643).

The regulation of vascular smooth muscle cells (VSMCs) function by taurine has been a subject of increasing interest and investigation, and taurine is taken up into cells through a specific transporter system, the taurine transporter (TAUT). In the present study, we examined the expression of TAUT in VSMCs and the kinetic parameters of the uptake process of TAUT in VSMCs. RT-PCR and western blot demonstrated that the mRNA and protein of TAUT was expressed in VSMCs in vitro. Immunohistochemistry using antibody for TAUT revealed the expression of this protein in rat thoracic aorta. The maximal [³H]taurine uptake rate in VSMCs was 37.75 ± 3.13 pmol/min per mg of protein, with a K m value of 5.42 ± 0.81 µM. Thus, VSMCs are able to express a functional taurine transporter. The regulation and detailed function of taurine and TAUT in VSMCs remain unclear, but our findings suggest a functional role for them in VSMCs metabolism.

Keywords: Keywords: Taurine transporter – Vascular smooth muscle cells – Kinetic analysis

Molecular cloning of a structural homolog of YY1AP, a coactivator of the multifunctional transcription factor YY1 by T. Ohtomo; T. Horii; M. Nomizu; T. Suga; J. Yamada (pp. 645-652).

YY1 is a multifunctional transcription factor that activates or represses gene transcription depending on interactions with other regulatory proteins that include coactivator YY1AP. Here, we describe the cloning of a novel homolog of YY1AP, referred to as YARP, from the human neuroblastoma cell line SK–N–SH. The cloned cDNA encoded a 2240 amino acid protein that contained a domain which was 97% homologous to an entire YY1AP sequence of 739 amino acids. Two splice variants, YARP2 and YARP3, were also cloned. Northern blotting demonstrated the YARP mRNA (∼10 kb), which was increased 1.7-fold after dibutyryl cAMP-induced neural differentiation of the cells. Presence of YARP mRNA was also confirmed in human tissues such as the heart, brain and placenta. Bioinformatic analysis predicted various functional motifs in the YARP structure, including nuclear localization signals and domains associated with protein–protein interactions (PAH2), DNA-binding (SANT), and chromatin assembly (nucleoplasmin-like), outside the YY1AP-homology domain. Thus, we propose that YARP is multifunctional and plays not only a role analogous to YY1AP, but also its own specific roles in DNA-utilizing processes such as transcription.

Keywords: Keywords: YY1-associated protein – YARP – Dingo – GON4L – Gene expression – Human

The digital language of amino acids by L. Kurić (pp. 653-661).

The subject of this paper is a digital approach to the investigation of the biochemical basis of genetic processes. The digital mechanism of nucleic acid and protein bio-syntheses, the evolution of biomacromolecules and, especially, the biochemical evolution of genetic language have been analyzed by the application of cybernetic methods, information theory and system theory, respectively. This paper reports the discovery of new methods for developing the new technologies in genetics. It is about the most advanced digital technology which is based on program, cybernetics and informational systems and laws. The results in the practical application of the new technology could be useful in bioinformatics, genetics, biochemistry, medicine and other natural sciences.

Keywords: Keywords: Amino acids code matrix – Digital genetic code – Mathematical evolution of genetics processes

1-(N-Trifluoroacetylamino)alkylphosphonic acids: synthesis and properties by Z. H. Kudzin; R. Depczyński; M. H. Kudzin; J. Łuczak; J. Drabowicz (pp. 663-667).

The 1-(N-trifluoroacetylamino)alkylphosphonic acids (TFA-AA^P) – sub-products in the synthesis of O,O-dialkyl 1-(N-trifluoroacetylamino)alkylphosphonates and O,O-diethyl 1-aminoalkylphosphonates, were synthesized in two-stage transformations of 1-aminoalkylphosphonic acids including: trifluoroacetylation of 1-aminoalkylphosphonic acids (AA^P) using a trifluoroacetic anhydride/trifluoroacetic acid reagent (AA^P + TFAA/TFA→2) and subsequent hydrolysis of the intermediary compounds 2 into desired TFA-AA^P (2→TFA-AA^P). These intermediates 2 presented mixtures of the type of mixed anhydrides of TFAA and 1-(N-trifluoroacetylamino)alkylphosphonic, pyrophosphonic and polyphosphonic acids, which underwent rapid and quantitative conversion to corresponding TFA-AA^P during treatment with an excess of water. The title acids were isolated by direct evaporation of the corresponding post-reaction mixtures, and their physicochemical proprieties, including deacylation abilities, were determined. TFA-AA^P compounds can be re-converted into the starting amino acids AA^P under respectively mild conditions (AA^P→TFA-AA^P→AA^P).

Keywords: Keywords: Acylation – Trifluoroacetylation – Mixed anhydrides – Aminophosphonic acids – 1-Aminoalkylphosphonic acids – 1-(N- Trifluoroacetylamino)alkylphosphonic acids

Prediction of mitochondrial proteins based on genetic algorithm – partial least squares and support vector machine by F. Tan; X. Feng; Z. Fang; M. Li; Y. Guo; L. Jiang (pp. 669-675).

Mitochondria are essential cell organelles of eukaryotes. Hence, it is vitally important to develop an automated and reliable method for timely identification of novel mitochondrial proteins. In this study, mitochondrial proteins were encoded by dipeptide composition technology; then, the genetic algorithm-partial least square (GA-PLS) method was used to evaluate the dipeptide composition elements which are more important in recognizing mitochondrial proteins; further, these selected dipeptide composition elements were applied to support vector machine (SVM)-based classifiers to predict the mitochondrial proteins. All the models were trained and validated by the jackknife cross-validation test. The prediction accuracy is 85%, suggesting that it performs reasonably well in predicting the mitochondrial proteins. Our results strongly imply that not all the dipeptide compositions are informative and indispensable for predicting proteins. The source code of MATLAB and the dataset are available on request under liml@scu.edu.cn.

Keywords: Keywords: Mitochondrial proteins – Dipeptide composition – Genetic algorithm-partial least square – Support vector machine

Differential responses to anxiogenic drugs in a mouse model of panic disorder as revealed by Fos immunocytochemistry in specific areas of the fear circuitry by I. Sahún; X. Gallego; M. Gratacòs; P. Murtra; R. Trullás; R. Maldonado; X. Estivill; M. Dierssen (pp. 677-688).

Sensitivity to pharmacological challenges has been reported in patients with panic disorder. We have previously validated transgenic mice overexpressing the neurotrophin-3 (NT-3) receptor, TrkC (TgNTRK3), as an engineered murine model of panic disorder. We could determine that TgNTRK3 mice presented increased cellularity in brain regions, such as the locus ceruleus, that are important neural substrates for the expression of anxiety in severe anxiety states. Here, we investigated the sensitivity to induce anxiety and panic-related symptoms by sodium lactate and the effects of various drugs (the α2-adrenoceptor antagonist, yohimbine and the adenosine antagonist, caffeine), in TgNTRK3 mice. We found enhanced panicogenic sensitivity to sodium lactate and an increased intensity and a differential pattern of Fos expression after the administration of yohimbine or caffeine in TgNTRK3. Our findings validate the relevance of the NT-3/TrkC system to pathological anxiety and raise the possibility that a specific set of fear-related pathways involved in the processing of anxiety-related information may be differentially activated in panic disorder.

Keywords: Keywords: Panic disorder – Fos immunohistochemistry – Amygdala – Locus ceruleus – TrkC – NT-3 – Yohimbine – Caffeine

Using C′ deviation to study structures of central amino acids in peptide fragments by H.-Y. Tang; Z.-G. Zhang (pp. 689-693).

In this investigation, we attempted to study the backbone geometry of amino acids in peptides using C′ deviation. Diameters of distribution were used to describe the various atomic structures, and scatter graphs provided visual evaluation. The length of peptide fragments and the secondary structure of amino acids in the central position of the peptide fragments were also analyzed. The results showed that the atomic distribution of the central amino acids of five-residue peptide fragments was much more restricted than that of their corresponding three-residue peptide fragments. In identical three-residue fragments, atoms of central amino acids with different secondary structures, were distributed in distinct areas.

Keywords: Keywords: Backbone geometry – C′ deviation – Peptide fragment – Fragment length – Secondary structure

Synthesis, cytotoxicity and clastogenicity of novel α-aminophosphonic acids by E. Naydenova; K. Troev; M. Topashka-Ancheva; G. Hägele; I. Ivanov; A. Kril (pp. 695-702).

α-Ethyl-N-(phosphonomethyl) glycine is synthesized and characterized by NMR and FAB spectroscopy. The cytotoxicity, clastogenic and antiproliferative effect of 3-ethyl-2-hydroxyl-2-oxo-1,4,2-oxazaphosphorinane, sodium salt of 3-ethyl-2-hydroxyl-2-oxo-1,4,2-oxazaphosphorinane, α-ethyl-α-N-(hydroxyethylamino) methylphosphonic acid, α-ethyl-N-(phosphonomethyl) glycine, α-ethyl-N-(phosphonomethyl) glycine isopropylammonium salt, glyphosate isopropylammonium salt are tested.

Keywords: Keywords: Aminophosphonic acids – N-(Phosphonomethyl) glycine – Cytotoxicity – Clastogenic – Antiproliferative effect

Peptidology: short amino acid modules in cell biology and immunology by G. Lucchese; A. Stufano; B. Trost; A. Kusalik; D. Kanduc (pp. 703-707).

Short amino acid motifs, either linear sequences or discontinuous amino acid groupings, can interact with specific protein domains, so exerting a central role in cell adhesion, signal transduction, hormone activity, regulation of transcript expression, enzyme activity, and antigen-antibody interaction. Here, we analyze the literature for such critical short amino acid motifs to determine the minimal peptide length involved in biologically important interactions. We report the pentapeptide unit as a common minimal amino acid sequence critically involved in peptide-protein interaction and immune recognition. The present survey may have implications in defining the dimensional module for peptide-based therapeutical approaches such as the development of novel antibiotics, enzyme inhibitors/activators, mimetic agonists/antagonists of neuropeptides, thrombolitic agents, specific anti-viral agents, etc. In such a therapeutical context, it is of considerable interest that low molecular weight peptides can easily cross biological barriers, are less susceptible to protease attacks, and can be administered at high concentrations. In addition, small peptides are a rational target for strategies aimed at antigen-specific immunotherapeutical intervention. As an example, specific short peptide fragments might be used to elicit antibodies capable of reacting with the full-length proteins containing the peptide fragment’s amino acid sequence, so abolishing the risk of cross-reactivity.

Keywords: Keywords: Regulatory peptides – Epitopic peptides – Minimal peptide length – Pentapeptide unit

Methods for syntheses of N-methyl-DL-aspartic acid derivatives by M. Boros; J. Kökösi; J. Vámos; I. Kövesdi; B. Noszál (pp. 709-717).

A novel practical method for the synthesis of N-methyl-DL-aspartic acid 1 (NMA) and new syntheses for N-methyl-aspartic acid derivatives are described. NMA 1, the natural amino acid was synthesized by Michael addition of methylamine to dimethyl fumarate 5. Fumaric or maleic acid mono-ester and -amide were regioselectively transformed into beta-substituted aspartic acid derivatives. In the cases of maleamic 11a or fumaramic esters 11b, the α-amide derivative 13 was formed, but hydrolysis of the product provided N-methyl-DL-asparagine 9 via base catalyzed ring closure to DL-α-methylamino-succinimide 4, followed by selective ring opening. Efficient methods were developed for the preparation of NMA-α-amide 13 from unprotected NMA via sulphinamide anhydride 15 and aspartic anhydride 3 intermediate products. NMA diamide 16 was prepared from NMA dimethyl ester 6 and methylamino-succinimide 4 by ammonolysis. Temperature-dependent side reactions of methylamino-succinimide 4 led to diazocinone 18, resulted from self-condensation of methylamino-succinimide via nucleophyl ring opening and the subsequent ring-transformation.

Keywords: Keywords: N-methyl-aspartic acid – Regioselective ester and amide formation – Ring transformations – Methylamino succinimide – Diazocinone

Spectroscopic, theoretical and structural characterization of hydrogensquarates of l-threonyl-l-serine and l-serine by T. Kolev; B. B. Koleva; M. Spiteller (pp. 719-725).

Hydrogensquarates of dipeptide l-threonyl-l-serine (H-Thr-Ser-OH) and l-serine (HSq × Ser) have been synthesized, isolated and spectroscopic characterized by solid-state linear-polarized IR-spectroscopy, ¹H- and ¹³C-NMR, ESI-MS and HPLC with tandem masspectrometry (MS-MS) methods. The structures of the salts and neutral dipeptide have been predicted theoretically by ab initio calculations. In the case of H-Thr-Ser-OH the theoretical data are supported by IR-LD ones. The hydrogensquarates consist in positive charged dipeptide or amino acid moiety and negative hydrogensquarate anion (HSq) stabilizing by strong intermolecular hydrogen bonds. The data about the l-serine hydrogensquarate are compared with known crystallographic data thus indicating a good correlation between the theoretical predicted structures and experimentally obtained by single crystal X-ray diffraction.

Keywords: Keywords: H-Thr-Ser-OH – Serine – Hydrogensquarates – Solid-state IR-LD – ab initio calculations – ¹H- and ¹³C-NMR – ESI-MS – HPLC-MS-MS

Sections

Personal tools

Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.33, #4)

Sections

Personal tools

Local resources

Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.33, #4)