Ω-amino Acids Research Articles

Apparent molal heat capacities of organic compounds in aqueous solution. Part 3.—ω-Amino acids and related compounds

Values of apparent molal heat capacities ΦCp in the range 23°–55°C, were determined by adiabatic calorimetry for the following amino acids: glycine, α-alanine, α-aminoisobutanoic acid, valine, serine, threonine, sarcosine, dimethylglycine, betaine, β-alanine, β- and γ-aminobutanoic acids, δ-aminopentanoic acid and Iµ-aminohexanoic acid. Some hydroxy acids, sodium and ammonium salts of carboxylic acids, methyl and ethyl esters of acetic acid and glycine methylester hydrochloride have also been studied.An attempt has been made to quantify the contribution to ΦCp associated with charge separation in amphionic molecules by comparing the experimental value (ΦexpCp) for amino acids with those for similar uncharged molecules (ΦrefCp). The ΔΦ* values (ΦexpCp–ΦrefCp) thus obtained for +H3N(CH2)m COO– compounds (m= 2, 3, 4, 5) are used in order to obtain some information about the interactions between neutral or charged amino and carboxylic groups. Effects connected with the methyl additions to N+ centres in glycine or ammonium salts are considered.

Gas chromatography-mass spectrometry of trimethylsilyl derivatives of ω-amino acids

The silylation of C 4C 11 ω-amino acids and their hydrochlorides was carried out with N,O-bis(trimethylsilyl)acetamide. Di-TMS and tri-TMS derivatives were formed in the silylation of the hydrochlorides. The formation of the two derivatives is dependent on the reaction conditions, and the conditions under which only one derivative arises reproducibly, are reported. This finding may be utilized in the quantitative analysis of amino acids.

Selective neuronal accumulation of ω-amino acids in the rabbit retina

The uptakes of radioactive glycine, beta-alanine, GABA, delta-aminovaleric acid and epsilon-aminocaproic acid were studied in the rabbit retina in vivo and in vitro. Autoradiography demonstrated that the amino acids were mainly taken up and retained by certain cells of amacrine type. In the neurons, the omega-amino acids seem to be stored in a protected fashion. The uptake of delta-aminovaleric acid and epsilon-aminocaproic acid was temperature dependent, saturable, and of high-affinity type (with Km for delta-aminovaleric acid = 3.02 X 10(-5) M and for epsilon-aminocaproic acid 9.38 X 10(-5) M). The uptake of both delta-aminovaleric acid and epsilon-aminocaproic acid was competitively inhibited by GABA, but not by glycine or a number of other amino acids regarded as possible neurotransmitters. The uptakes of delta-aminolevulinic acid, taurine and alpha-amino-isobutyric acid were studied for comparison, but no selective neuronal uptake was observed. It is concluded that there are certain amacrine cells which selectively accumulate delta-amino acids such as beta-alanine, GABA, delta-aminovaleric acid and epsilon-aminocaproic acid. It seems possible that the mechanism accumulating GABA may also work with the other omega-amino acids. This opens the possibility that the omega-amino acids may serve as 'false neurotransmitters'.

ω‐アミノ酸の自動分析装置

An auto-analyzer of ω-amino acids has been set up by incorporating a reaction system of the phenol-sodium hypochlorite color reaction specific for ω-amino acids into a commercial, multi-line amino-acid analyzer. Conditions of the color reaction has been modified from those of ordinary test-tube reaction so as to obtain reproducible and highly sensitive analyses of ω-amino acids in biological materials by using this apparatus. As applications, free and bound-form ω-amino acids in some wild mushrooms have been analyzed and β-alanine formed by the action of aspartate α-decarboxylase on aspartic acid has been determined.

The structure-activity relationship for gaba and related compounds in the crayfish muscle

The increase in membrane conductance in crayfish muscle produced by γ-aminobutyric acid (GABA) was measured and compared with the effect of various structurally related compounds. The mode of action of these substances was analyzed by measuring the maximal conductance increase and the reciprocal of the half maximal concentration (apparent affinity), derived from the dose-conductance curve. Among the substances tested, GABA showed the highest values both in affinity and maximal conductance increase. Lengthening or shortening the chain length of ω-amino acids decreased the affinity and maximal conductance. ω-Guanidino acids induced only a small conductance increase in the normal Van Harreveld's solution, while their affinity was high compared with analogues of ω-amino acids. Addition of neutral side groups to GABA decreased the effectiveness, particularly its affinity. The mechanism of the action of inhibitory substances is discussed. Distance between positive and negative charges on a compound may be the most important factor that determines affinity, but additional factors may play a role in producing the conductance change.

ChemInform Abstract: HYDROGENATION OF 6‐CYANOHEXANOIC ACID

AbstractDie durch Umsetzung von e‐Caprolacton (I) mit Natriumcyanid erhältliche 6‐Cyanhexansäure (II) ergibt durch Reduktion mit Raney‐ oder Urushibara‐Kobalt in ver= dünntem Ammoniak in hoher Ausbeute 7‐Aminoheptansäure (III).

Crystal and Molecular Structure of ω-Amino Acids, ω-Amino-Sulfonic Acids and Their Derivatives. VII. The Crystal and Molecular Structure of Dl-Carnitine Hydrochloride

Abstract The crystal structure of Dl-carnitine hydrochloride, C7H15NO3·HCl, was determined by the heavy atom method using X-ray diffraction data on a Weissenberg photograph, and refined by the least-squares method to an R-factor of 0.13 for 1969 independent reflections. The crystals are monoclinic space group P21⁄c, Z=4, with a=6.77(1), b=11.41(2), c=15.10(3) Å and β=120.1(1)°. By protonation at carboxyl oxygen atom, carnitine molecule has the cationic form, N+(CH3)3CH2CH(OH)CH2COOH, with trans-zigzag skeletal configuration as similar as γ-amino-β-hydroxybutyric acid. The Cl− ion mediates between adjacent carnitine cations by two O–H···Cl− hydrogen bonds to form infinite chain elongated along the c-axis. The correlation between molecular structure and biological activity was also discussed.

Hydrogenation of 6-Cyanohexanoic Acid

Reduction of 6-cyanohexanoic acid, obtained by the reaction of e-caprolactone with alkali metal cyanide, was studied with cobalt or nickel catalysts. Cobalt catalysts such as Raney Co and Urushibara Co gave 7- aminoheptanoic acid in high yields in dilute ammonia solutions. On the other hand nickel catalysts gave much more iminodiheptanoic acid and much less ω-amino acid. In addition, separation of nickel ion generated in the reaction was more difficult than that of cobalt ion. Some other ω-amino acids were obtained by the above-mentioned operation.

Studies on colistin nonapeptide derivatives. III. Chemical synthesis and characterization of n-fattyacyl mono-aminoacyl derivatives of colistin nonapeptide.

In order to examine the antimicrobial activity of n-fattyacyl mono-aminoacyl derivatives of colistin nonapeptide (CNP), twenty-one derivatives were synthesized and characterized on their chemical, physicochemical and antimicrobial properties. Five α-amino acids, glycine, l-alanine, dl-aminobutyric acid, dl-norvaline and dl-norleucine, and two ω-amino acids, β-alanine and γ-aminobutyric acid, were first acylated with each of three kinds of acid chloride, n-octanoyl, n-decanoyl and n-dodecanoyl chloride, and then esterified with p-nitrophenol prior to the coupling of those n-fattyacyl amino acids to the terminal threonine of CNP. The coupling reaction was carried out in an aqueous solvent buffered at pH 5.0 without any protection of the γ-amino groups of CNP, as reported previously.All of the derivatives obtained in hydrochloride salts were hygroscopic white amorphous powder showing decomposing points at 180~230°C. Each purified preparation exhibited a ninhydrin positive spot on a paper chromatogram, and ea...

Transition and relaxation processes in ω-amino acid polyamides

Differential thermal analysis has been used to study the thermal transitions that occur on heating efficiently quenched samples of ω-amino acid polyamides. With ‘even’ amino acid polyamides (nylons-4, -6, -8, etc.) an endothermic type of transition was observed in the region of 30–40°C; this was followed immediately by an exothermic transition. No such transitions were observed with the ‘odd’ polyamides (nylons-5, -7, -11, etc.). From X-ray diffraction spectra and structural considerations, these transitions have been shown to be associated with the formation of hydrogen-bonded structures, that are possible with ‘even’ polyamides, but not with the ‘odd’ members. From a combination of differential thermal analysis, density and X-ray diffraction data, a new picture of the low temperature crystallization behaviour of this type of polyamide has emerged.

Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. VI. The Crystal and Molecular Structure of Dl-γ-Amino-β-hydroxybiityric Acid (GABOB), A Nervous Inhibitory Chemical Transmitter

Abstract Dl-γ-Amino-β-hydroxybutyric acid (GABOB), C4H9O3N, forms monoclinic plate crystals of space group P21/c, with a=7.43, b=8.29, c=9.34 Å, β=110.9°, and four molecules in the unit cell. Intensity data were collected by a film method. The structure was solved by the direct method with the symbolic addition procedure, and refined by least-squares methods to R=0.096. GABOB molecule having the zwitterionic structure, NH3+–CH2–CH(OH)–CH2–COO^-, forms trans-zigzag skeletal conformation with an intramolecular OH···O hydrogen bond of 2.773 Å, and contacts with each other by three dimensional network of NH···O and OH···O hydrogen bonds.

Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. V. Crystal and Molecular Structure of γ-Guanidino Propane Sulfonic Acid

Abstract The crystal structure of γ-guanidino propane sulfonic acid was determined by the symbolic addition method with X-ray intensity data on a diffractometer and refined by the least-squares method to an R-value 0.069 for 1963 reflections. The crystals were monoclinic, space group P21/c, Z=8, with a=10.080, b=8.013, c=19.716 Å and β=98.17°. Two independent molecules in the asymmetric unit both have a zwitterionic form, (NH2)2+CNHCH2CH2CH2SO3−. There are two forms, trans zigzag and cis ones, which are linked by N(1)H···O hydrogen bonds. The molecules are held together in the crystal by a three-dimensional network of NH···O hydrogen bonds.

Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. III. The Crystal and Molecular Structure of γ-Guanidino-β-hydroxypropane Sulfonic Acid

Abstract γ-Guanidino-β-hydroxypropane sulfonic acid C4H11O4N3S crystallizes in the monoclinic space group P21/c, with four formula units in a unit cell of dimensions, a=7.44, b=9.89, c=11.11 Å and β=97.75°. The crystal structure was determined by the heavy atom method and refined by block-diagonal least-squares to an R-value of 0.12 using intensity data collected photographically. The molecule takes the zwitterionic form, (NH2)2+CNH-CH2CH(OH)CH2SO3−. The skeletal conformation of the molecule is planar trans zigzag. The molecules are held together in the crystal by a three-dimensional network of NH···O and OH···O hydrogen bonds.

Crystal and Molecular Structure of ω-Amino Acids, ω-Amino Sulfonic Acids and Their Derivatives. IV. The Crystal and Molecular Structure of γ-Aminobutyric Acid (GABA), a Nervous Inhibitory Transmitter

Abstract The structure of γ-aminobutyric acid (GABA), C4H9NO2, was determined by single-crystal X-ray diffraction analysis using the data collected on a four-circle diffractometer. The compound was crystallized from an aqueous ethanol solution as needles of the monoclinic space group P21/c with four molecules in the following unit cell; a=7.193, b=10.120, c=8.260 Å and β=111.05°. The structure was solved directly by a symbolic addition method and refined by a least-squares procedure. The final R is 9.3%. The molecular geometry is not a planar trans-zigzag configuration as found in γ-guanidinobutyric acid hydrochloride or homotaurine, but a gauche configuration with respect to Cα–Cβ bond. The expected zwitterionic structure is evident from the locations of the hydrogen atoms in a difference Fourier map, each molecule being connected with three N–H···O hydrogen bonds to form a three-dimensional network.

Spectrophotometric Determination of Glyoxylic Acid witho-Aminobenzaldehyde and Glycine, and Its Application to Enzyme Assay

Glyoxylic acid reacted with o-aminobenzaldehyde and glycine to yield a yellow product, whose absorption maximum was at 440 mµ. Glycine could be replaced by ω-amino acids, e.g., γ-aminobutyrate, and aliphatic amines, but not by α-amino acids. The effects of pH, kind and concentration of buffers, concentration of o-aminobenzaldehyde, and incubation time on the reaction were investigated to establish the optimum conditions. Microamounts of glyoxylate (0.05~1.5 µmoles) were determined rapidly by this simple method with satisfactory results, α-Keto acids such as α-ketoglutarate reacted far less effectively ; almost no appreciable interference with quantitative estimation of glyoxylate occurred with them. This procedure is applicable for the assay of enzymes which catalyze the formation of glyoxylate, e.g., isocitrate lyase and glycollate oxidase.

Crystal structure of copper(II) complexes with ω-amino acids. I. Copper(II) di-γ-aminobutyrate, [Cu(NH2CH2CH2CH2COO)2]n, and its dihydrate [Cu(NH2CH2CH2CH2COO)2.2H2O

Crystal structure of copper(II) complexes with ω-amino acids. I. Copper(II) di-γ-aminobutyrate, [Cu(NH2CH2CH2CH2COO)2]n, and its dihydrate [Cu(NH2CH2CH2CH2COO)2.2H2O

Spectrophotometric Determination of Glyoxylic Acid with o-Aminobenzaldehyde and Glycine, and Its Application to Enzyme Assay

Glyoxylic acid reacted with o-aminobenzaldehyde and glycine to yield a yellow product, whose absorption maximum was at 440 mµ. Glycine could be replaced by ω-amino acids, e.g., γ-aminobutyrate, and aliphatic amines, but not by α-amino acids. The effects of pH, kind and concentration of buffers, concentration of o-aminobenzaldehyde, and incubation time on the reaction were investigated to establish the optimum conditions. Microamounts of glyoxylate (0.05~1.5 µmoles) were determined rapidly by this simple method with satisfactory results, α-Keto acids such as α-ketoglutarate reacted far less effectively ; almost no appreciable interference with quantitative estimation of glyoxylate occurred with them. This procedure is applicable for the assay of enzymes which catalyze the formation of glyoxylate, e.g., isocitrate lyase and glycollate oxidase.

Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. I. The Crystal and Molecular Structure of γ-Guanidinobutyric Acid Hydrochloride and Hydrobromide

Abstract The crystals of γ-guanidinobutyric acid (GGBA) hydrochloride and hydrobromide, C5H12O2N3Cl and C5H12O2N3Br, are both triclinic, space group P\bar1, with two molecules in a unit cell with the following dimensions; hydrochloride: a=7.41, b=9.12, c=7.25 Å, α=101.5°, β=112.4°, γ=65.2°; hydrobromide: a=7.94, b=9.36, c=7.78 Å, α=103.2°, β=115.5°, γ=61.5°. The X-ray structure analysis was carried out by the application of heavy atom method and refined by three dimensional least-squares method. Since GGBA hydrochloride and hydrobromide are isomorphous, the structure analysis was started by using of X-ray data of the hydrobromide to determine the rough atomic coordinates of its molecule, and the data of hydrochloride were used for the further refinement. The positions of the involved twelve hydrogen atoms were located by a three dimensional difference Fourier analysis. GGBA cation, +NH2(NH2)CNH(CH2)3COOH, and Cl− ion were almost perfectly on the (20\bar1) plane and formed a pararell sheet structure with six hydrogen bonds. The possible resonance structures were also discussed.

Crystal and Molecular Structure of ω-Amino Acids, ω-Amino Sulfonic Acids and Their Derivatives. II. The Crystal and Molecular Structure of α-Form of 3-Aminopropane Sulfonic Acid, Homotaurine

Abstract From ethanol aqueous solution, two forms of crystals of 3-aminopropane sulfonic acid (homotaurine) have been obtained in different crystal systems. The α-form is orthorhombic, space group Pmn21, with two molecules in a unit cell of the dimensions; a=7.059, b=5.492 and c=7.428 Å. The X-ray structure analysis was carried out by the application of usual heavy atom method and refined by three dimensional least-squares procedure. The final R-value is 0.059. In the crystalline state, homotaurine molecule has the zwitterionic structure, NH3+–CH2–CH2–CH2–SO3−, with trans-zigzag skeletal configuration, and non-hydrogen atoms except two oxygen atoms lie exactly on a mirror plane. Each molecule in the crystal is connected by three dimensional network of three NH···O hydrogen bonds.

Effects of glycine and GABA, and blocking actions of strychnine and picrotoxin in the hypoglossus nucleus.

Neutral ω-amino acids were applied iontophoretically in the hypoglossus nucleus. Intracellular recordings revealed inhibitory actions involving hyperpolarization and conductance increase of the membrane. The antidromic field potential was reduced most effectively by glycine, as judged by the comparison of iontophoretic currents. Picrotoxin, ejected electrophoretically, clearly interfered with the action of GABA, glycine effects being reduced only with rather high currents. Strychnine had very specific blocking ability against glycine actions.