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Dieter Rewicki - One of the best experts on this subject based on the ideXlab platform.
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Mechanistic Studies on the Formation of Maillard Products from [1-13C]-D-Fructose
Maillard Reactions in Chemistry Food and Health, 2005Co-Authors: Dieter Rewicki, Evelyn Kersten, Bernd Helak, C. Nittka, Roland TresslAbstract:Ketoses are known to react with amino compounds via ketimines to form the so-called Heyns compounds (2-aminoaldoses), which are assumed to undergo subsequent transformations parallel to those observed with the corresponding Amadori compounds. Until now, this assumption was not established by separate mechanistic studies. Therefore, we prepared [1- 13 C]-D-fructose from [1- 13 C]-D-glucose by enzymatic methods. In a series of model experiments [1- 13 C]-D-fructose was heated with 4-Aminobutyric Acid (Strecker inactive), L-isoleucine (Strecker active), and L-proline (secondary amine type), respectively. The labeled products were analyzed by capillary GC/MS and NMR spectroscopy and the labeling characteristics were examined from MS data. Compared to corresponding experiments with [1- 13 C]-D-glucose, the significant results are: (1) With 4-Aminobutyric Acid only trace amounts of 3-deoxyaldoketose products are formed in the D-fructose system, whereas 1-deoxydiketose products were generated in comparable amounts from D-glucose and D-fructose; and (2) With L-isoleucine both D-glucose and D-fructose form 3-deoxyaldoketose- and 1-deoxydiketose products in comparable amounts; but with D-fructose the most effective reaction is the formation of pyrazines initiated by a retro aldol cleavage into C 3 +C 3 fragments. This cleavage is also responsible for the formation of mixtures of isotopomeric products in D-fructose systems.
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Structure and potential cross-linking reactivity of a new pentose-specific Maillard product
Journal of Agricultural and Food Chemistry, 1994Co-Authors: Roland Tressl, Evelyn Kersten, Georg T. Wondrak, Dieter RewickiAbstract:The Maillard reaction of model compounds for peptide-bound lysine (4-Aminobutyric Acid, 6-aminocaproic Acid, N α -acetyl-L-lysine) with reducing sugars (D-ribose, D-xylose, D-arabinose, D-glucose, D-fructose, D-glyceraldehyde) was investigated under both stringent and mild conditions. With pentoses the corresponding ω-(dimethylmaleimido)carboxylic Acids 1-3 were identified as substantial, hitherto unknown components by GC/MS and NMR. Their structure was confirmed by synthesis. A pathway to compounds 1-3 was derived from the results of 4-Aminobutyric Acid/[ 13 C]-D-arabinose isotopic labeling experiments
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Formation of pyrroles, 2-pyrrolidones, and pyridones by heating of 4-Aminobutyric Acid and reducing sugars
Journal of Agricultural and Food Chemistry, 1993Co-Authors: Roland Tressl, Evelyn Kersten, Dieter RewickiAbstract:The Maillard reaction of 4-Aminobutyric Acid with reducing sugar (D-arabinose, D-glucose, L-rhamnose, D-fructose, maltose) was investigated in slightly Acidic aqueous media. Eight pyrroles, 14 2-pyrrolidones, and 2 4-pyridones were characterized and quantified by capillary GC/MS. For structure elucidation the compounds were separated by preparative GC or synthesized and investigated by MS, IR, and 1 H NMR spectroscopy. Due to a blocked Strecker degradation, the 4-Aminobutyric Acid specific Maillard products are comparable to those of peptide-bound L-lysine. Thus, the title compounds generated in D-glucose and maltose/4-Aminobutyric Acid model experiments are structurally related to E-pyrrolonorleucine and maltosine, respectively
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Formation of 4-Aminobutyric Acid specific Maillard products from [1-13C]-D-glucose, [1-13C]-D-arabinose, and [1-13C]-D-fructose
Journal of Agricultural and Food Chemistry, 1993Co-Authors: Roland Tressl, Evelyn Kersten, Dieter RewickiAbstract:The Maillard reaction of 1- 13 C-labeled D-glucose, D-arabinose, and D-fructose with 4-Aminobutyric Acid was investigated. The extent and position of the isotopic labeling (from MS data) were used to evaluate origin, reactive intermediates, and formation pathways of pyrroles, 2-pyrrolidones, and some related products. The results are representative for peptide-bound lysine and systems with blocked Strecker amines. The observed distribution of the label supports 3-deoxyaldoketoses as intermediates of 2-formylpyrroles 1/3 and disqualifies 4-deoxy- and 1-deoxydiketose routes to 2-acetylpyrroles 2/4, respectively
Roland Tressl - One of the best experts on this subject based on the ideXlab platform.
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Mechanistic Studies on the Formation of Maillard Products from [1-13C]-D-Fructose
Maillard Reactions in Chemistry Food and Health, 2005Co-Authors: Dieter Rewicki, Evelyn Kersten, Bernd Helak, C. Nittka, Roland TresslAbstract:Ketoses are known to react with amino compounds via ketimines to form the so-called Heyns compounds (2-aminoaldoses), which are assumed to undergo subsequent transformations parallel to those observed with the corresponding Amadori compounds. Until now, this assumption was not established by separate mechanistic studies. Therefore, we prepared [1- 13 C]-D-fructose from [1- 13 C]-D-glucose by enzymatic methods. In a series of model experiments [1- 13 C]-D-fructose was heated with 4-Aminobutyric Acid (Strecker inactive), L-isoleucine (Strecker active), and L-proline (secondary amine type), respectively. The labeled products were analyzed by capillary GC/MS and NMR spectroscopy and the labeling characteristics were examined from MS data. Compared to corresponding experiments with [1- 13 C]-D-glucose, the significant results are: (1) With 4-Aminobutyric Acid only trace amounts of 3-deoxyaldoketose products are formed in the D-fructose system, whereas 1-deoxydiketose products were generated in comparable amounts from D-glucose and D-fructose; and (2) With L-isoleucine both D-glucose and D-fructose form 3-deoxyaldoketose- and 1-deoxydiketose products in comparable amounts; but with D-fructose the most effective reaction is the formation of pyrazines initiated by a retro aldol cleavage into C 3 +C 3 fragments. This cleavage is also responsible for the formation of mixtures of isotopomeric products in D-fructose systems.
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Structure and potential cross-linking reactivity of a new pentose-specific Maillard product
Journal of Agricultural and Food Chemistry, 1994Co-Authors: Roland Tressl, Evelyn Kersten, Georg T. Wondrak, Dieter RewickiAbstract:The Maillard reaction of model compounds for peptide-bound lysine (4-Aminobutyric Acid, 6-aminocaproic Acid, N α -acetyl-L-lysine) with reducing sugars (D-ribose, D-xylose, D-arabinose, D-glucose, D-fructose, D-glyceraldehyde) was investigated under both stringent and mild conditions. With pentoses the corresponding ω-(dimethylmaleimido)carboxylic Acids 1-3 were identified as substantial, hitherto unknown components by GC/MS and NMR. Their structure was confirmed by synthesis. A pathway to compounds 1-3 was derived from the results of 4-Aminobutyric Acid/[ 13 C]-D-arabinose isotopic labeling experiments
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Formation of pyrroles, 2-pyrrolidones, and pyridones by heating of 4-Aminobutyric Acid and reducing sugars
Journal of Agricultural and Food Chemistry, 1993Co-Authors: Roland Tressl, Evelyn Kersten, Dieter RewickiAbstract:The Maillard reaction of 4-Aminobutyric Acid with reducing sugar (D-arabinose, D-glucose, L-rhamnose, D-fructose, maltose) was investigated in slightly Acidic aqueous media. Eight pyrroles, 14 2-pyrrolidones, and 2 4-pyridones were characterized and quantified by capillary GC/MS. For structure elucidation the compounds were separated by preparative GC or synthesized and investigated by MS, IR, and 1 H NMR spectroscopy. Due to a blocked Strecker degradation, the 4-Aminobutyric Acid specific Maillard products are comparable to those of peptide-bound L-lysine. Thus, the title compounds generated in D-glucose and maltose/4-Aminobutyric Acid model experiments are structurally related to E-pyrrolonorleucine and maltosine, respectively
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Formation of 4-Aminobutyric Acid specific Maillard products from [1-13C]-D-glucose, [1-13C]-D-arabinose, and [1-13C]-D-fructose
Journal of Agricultural and Food Chemistry, 1993Co-Authors: Roland Tressl, Evelyn Kersten, Dieter RewickiAbstract:The Maillard reaction of 1- 13 C-labeled D-glucose, D-arabinose, and D-fructose with 4-Aminobutyric Acid was investigated. The extent and position of the isotopic labeling (from MS data) were used to evaluate origin, reactive intermediates, and formation pathways of pyrroles, 2-pyrrolidones, and some related products. The results are representative for peptide-bound lysine and systems with blocked Strecker amines. The observed distribution of the label supports 3-deoxyaldoketoses as intermediates of 2-formylpyrroles 1/3 and disqualifies 4-deoxy- and 1-deoxydiketose routes to 2-acetylpyrroles 2/4, respectively
S.s. Jayabalakrishnan - One of the best experts on this subject based on the ideXlab platform.
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A volumetric and viscometric study of 4-Aminobutyric Acid in aqueous solutions of metformin hydrochloride at 308.15, 313.15 and 318.15k
Journal of the Serbian Chemical Society, 2011Co-Authors: K. Rajagopal, S.s. JayabalakrishnanAbstract:Density (ρ) and viscosity (η) measurements were performed for 4-Aminobutyric Acid in 0.05, 0.10 and 0.15 M aqueous metformin hydrochlo- ride at 308.15, 313.15 and 318.15 K. The measured values of density and vis- cosity were used to estimate some important parameters, such as the partial molal volume, V φ , the standard partial molal volume, V φ , the standard partial molal volume of transfer, ΔV φ , the hydration number, n H , the second derivative of the infinite dilution of the standard partial molal volume with temperature ∂ 2 V φ /∂T 2 , the viscosity B-coefficients, variation of B with temperature, dB/dT, the free energy of activation per mole of solvent Δμ 1 * and solute Δμ 2 * of the amino Acid in a ternary system. These parameters were interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.
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Ultrasonic Studies of 4-Aminobutyric Acid in Aqueous Metformin Hydrochloride Solutions at Different Temperatures
International Journal of Thermophysics, 2010Co-Authors: K. Rajagopal, S.s. JayabalakrishnanAbstract:Ultrasonic speeds and density data of 4-Aminobutyric Acid in 0.05 M, 0.10 M, and 0.15 M aqueous metformin hydrochloride (MFHCl) solutions are measured at 308.15 K, 313.15 K, and 318.15 K. The isentropic compressibility (k S ), the change in isentropic compressibility (Δk S ), the relative change in isentropic compressibility (\({\Delta k_S/k_S^0}\)), the apparent molal compressibility (\({k_\phi}\)), the limiting apparent molal compressibility (\({k_\phi^0 }\)), the transfer limiting apparent molal compressibility (\({\Delta k_\phi^0}\)), the hydration number (n H), and the pair and triplet interaction parameters (k AH, k AHH) are estimated. The above parameters are used to interpret the solute–solute and solute–solvent interactions of 4-Aminobutyric Acid in aqueous MFHCl solutions.
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Ultrasonic Studies of 4-Aminobutyric Acid in Aqueous Salbutamol Sulphate Solutions at Different Temperatures
Chinese Journal of Chemical Engineering, 2010Co-Authors: K. Rajagopal, S.s. JayabalakrishnanAbstract:Abstract Ultrasonic speeds of 4-Aminobutyric Acid in 0.0041, 0.0125 and 0.0207 mol·kg −1 aqueous salbutamol sulphate (SBS) solutions are measured at 308.15, 313.15 and 318.15 K. Isentropic compressibility K S , change in isentropic compressibility Δ K S , relative change in isentropic compressibility (Δ K S / K 0 S ), apparent molal compressibility K o , limiting apparent molal compressibility K 0 o , transfer limiting apparent molal compressibility δ K 0 o , hydration number n H , pair and triplet interaction parameters K AS , K ASS are estimated. The above parameters are used to interpret the solute-solute and solute-solvent interactions of 4-Aminobutyric Acid in the aqueous salbutamol sulphate solutions.
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Volumetric and Viscometric Studies of 4-Aminobutyric Acid in Aqueous Solutions of Salbutamol Sulphate at 308.15, 313.15 and 318.15 K
Chinese Journal of Chemical Engineering, 2009Co-Authors: K. Rajagopal, S.s. JayabalakrishnanAbstract:Abstract Density (ρ) and viscosity (η) measurements were carried out for 4-Aminobutyric Acid in 0.0041, 0.0125 and 0.0207 mol·L−1 aqueous salbutamol sulphate at 308.15, 313.15 and 318.15 K. The measured values of density and viscosity were used to estimate some important parameters such as apparent molar volume Vϕ, limiting apparent molar volume V ϕ 0 , transfer volume Δ V ϕ 0 , hydration number nH, second derivative of infinite dilution of partial molar volume with temperature ∂ 2 V ϕ 0 / ∂ T 2 , viscosity B-coefficients, variation of B with temperature dB/dT, free energy of activation per mole of solvent Δ μ 1 0 * and solute Δ μ 2 0 * , activation entropy Δ S 2 0 * and activation enthalpy Δ H 2 0 * of the amino Acids. These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.
Alcira M. Del C. Batlle - One of the best experts on this subject based on the ideXlab platform.
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Evidence that 4-Aminobutyric Acid and 5-aminolevulinic Acid share a common transport system into Saccharomyces cerevisiae.
The international journal of biochemistry & cell biology, 1995Co-Authors: Mariana Bermudez Moretti, Susana Correa Garcia, Mónica S. Chianelli, Eugenia Ramos, James R. Mattoon, Alcira M. Del C. BatlleAbstract:It has been previously reported that 5-aminolevulinic Acid (ALA) and 4-Aminobutyric Acid (GABA) share a common permease in Saccharomyces cerevisiae (Bermudez Moretti et al., 1993). The aim of the present work was to determine the relationship between the transport of these compounds in isolated cells. Assessment of amino Acid incorporation was performed in S. cerevisiae using 14C-ALA or 3H-GABA. Initial rates of ALA incorporation in cells grown in the presence of 5 mM ALA and 5 mM GABA, were three to four times lower than in cells grown without supplements. Kinetic studies indicate that GABA competitively inhibits ALA transport. During the growth phase GABA uptake was also inhibited by 74% and 60% in the presence of ALA and GABA, respectively. These findings indicate that in S. cerevisiae the structurally related compounds, ALA and GABA, may be incorporated into the cells by a common carrier protein. Should this occur in other lukaryotic cells it may explain the neurotoxic effect attributed to ALA in the pathogenesis of acute porphyrias.
Jordi Puiggalí - One of the best experts on this subject based on the ideXlab platform.
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synthesis of poly ester amide s derived from glycolic Acid and the amino Acids β alanine or 4 Aminobutyric Acid
Macromolecular Chemistry and Physics, 2003Co-Authors: Alfonso Rodriguezgalan, Katia Jiménez, Montserrat Vera, Lourdes Franco, Jordi PuiggalíAbstract:Full Paper: The polymerization of metal salts of N-chloroacetyl-β-alanine and N-chloroacetyl-4-Aminobutyric Acid was investigated. The former gives a mixture of polymer and a seven-membered cyclic compound constitued of glycolic and β-alanine units, and its reaction proceeds in the solid state. However, liquefaction is observed in the second case giving rise to a polymer with a moderate molecular weight. Condensation kinetics of both sodium and silver salts of N-chloroacetyl-β-alanine have been studied by differential scanning calorimetry. Copolymers of glycolic Acid and β-alanine with a molar ratio of glycolic Acid/β-alanine varying from 0.5 to 1.0 have been synthesized by thermal reaction of co-precipitated crystals of the sodium salts of chloroacetic Acid and N-chloroacetyl-β-alanine. NMR spectroscopy indicates that copolymers tend to have a random distribution. The resulting new poly(ester amide)s have been characterized by spectroscopy and thermal analysis.
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Synthesis of Poly(ester amide)s Derived from Glycolic Acid and the Amino Acids: β‐Alanine or 4‐Aminobutyric Acid
Macromolecular Chemistry and Physics, 2003Co-Authors: Alfonso Rodríguez-galán, Montserrat Vera, Katia Jiménez, Lourdes Franco, Jordi PuiggalíAbstract:Full Paper: The polymerization of metal salts of N-chloroacetyl-β-alanine and N-chloroacetyl-4-Aminobutyric Acid was investigated. The former gives a mixture of polymer and a seven-membered cyclic compound constitued of glycolic and β-alanine units, and its reaction proceeds in the solid state. However, liquefaction is observed in the second case giving rise to a polymer with a moderate molecular weight. Condensation kinetics of both sodium and silver salts of N-chloroacetyl-β-alanine have been studied by differential scanning calorimetry. Copolymers of glycolic Acid and β-alanine with a molar ratio of glycolic Acid/β-alanine varying from 0.5 to 1.0 have been synthesized by thermal reaction of co-precipitated crystals of the sodium salts of chloroacetic Acid and N-chloroacetyl-β-alanine. NMR spectroscopy indicates that copolymers tend to have a random distribution. The resulting new poly(ester amide)s have been characterized by spectroscopy and thermal analysis.
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A sheet structure in an alternate copolymer of 4-Aminobutyric Acid and α-isobutyl-l-glutamate
Polymer, 2000Co-Authors: María Teresa Casas, Jordi PuiggalíAbstract:Abstract An alternating copolyamide derived from 4-Aminobutyric Acid and α-isobutyl- l -glutamate has been synthesized by the active ester method, and subsequently characterized. The structure and morphology of lamellar crystals have been investigated by using transmission electron microscopy. Additional data have been obtained from uniaxially oriented films by using X-ray diffraction. Experimental results agree with an orthorhombic unit cell of parameters a=4.88, b=14.0 and the chain axis c=10.5 A . A sheet structure with intermolecular hydrogen bonds was deduced taking also into account infrared dichroism data.
