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Thomas Henle - One of the best experts on this subject based on the ideXlab platform.
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N-ε-fructosyllysine and N-ε-carboxymethyllysine, but not Lysinoalanine, are available for absorption after simulated gastrointestinal digestion
Amino Acids, 2014Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N -ε-fructoselysine, N -ε-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
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n e fructosyllysine and n e carboxymethyllysine but not Lysinoalanine are available for absorption after simulated gastrointestinal digestion
Amino Acids, 2014Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N-e-fructoselysine, N-e-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
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N-ε-fructosyllysine and N-ε-carboxymethyllysine, but not Lysinoalanine, are available for absorption after simulated gastrointestinal digestion
Amino acids, 2013Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N-e-fructoselysine, N-e-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
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Detection and identification of the cross-linking amino acidsN ^τ-andN ^π-(2′-amino-2′-carboxy-ethyl)-l-histidine (“histidinoalanine”, HAL) in heated milk products
Zeitschrift für Lebensmittel-Untersuchung und Forschung, 1993Co-Authors: Thomas Henle, Axel W. Walter, Henning KlostermeyerAbstract:In Säurehydrolysaten erhitzter Magermilch konnte am Aminosäureanalysator im Elutionsbereich zwischen Phenylalanin und Pyridosin eine unbekannte Verbindung, X, nachgewiesen werden, deren Bildung mit der Erhitzungszeit und -temperatur korrelierte. Durch präparative Ionenaustauschchromatographie gelang die Isolierung von X und einer zweiten Minorkomponente aus einem Milchproteinhydrolysat sowie einem Modellansatz bestehend aus N^α-Acetylhistidin undx` 2-Acetamidoacrylsäuremethylester (“Acetyldehydroalaninmethylester”) im Mengenverhältnis von 8 zu 1.^1H-NMR-spektroskopische Untersuchungen ermöglichten die eindeutige Identifizierung der beiden Verbindungen als N^τ- und N^π-Isomer von N -(2′-Amino-2′-carboxyethyl)- l -histidin (“Histidinoalanin”). Diese Crosslink-Aminosäuren waren bisher noch nicht in Lebensmitteln nachgewiesen worden. Die Gehalte an N^τ-Histidinoalanin in einer Anzahl milchproteinhaltiger Lebensmittel lagen mit 50 bis 1800 mg/kg Protein in einer mit der simultan quantifizierten, potentiell nierentoxischen Crosslink-Aminosäure Lysinoalanin vergleichbaren Größenordnung. An unknown ninhydrin positive compound, X, was detected in acid hydrolysates of heated skim milk samples by amino acid analysis, eluting between phenylalanine and pyridosine in the chromatogram. The formation of X correlated with heating time and temperature. preparative ion-exchange chromatography enabled the isolation of X and a second minor compound from a milk protein hydrolysate and from a model mixture consisting of N^α-acetylhistidine and methyl-2-acetamidoacrylate (acetyldehydroalaninmethylester), in a relative abundance of 8 to 1. By^1H-NMR spectroscopy, the two compounds could be identified as the N^τ- and N^π-isomers of N-(2′-amino-2′-carboxy-ethyl)- l -histidine (histidinoalanine), a cross-link amino acid that has not been described in food proteins up to now. In a number of foods containing milk protein, the N^τ-histidinoalanine contents were between 50 and 1800 mg/kg protein, which is in a concentration range comparable to the potential nephrotoxic cross-link Lysinoalanine, which was determined simultaneously.
Jan A. Delcour - One of the best experts on this subject based on the ideXlab platform.
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Identification of lanthionine and Lysinoalanine in heat-treated wheat gliadin and bovine serum albumin using tandem mass spectrometry with higher-energy collisional dissociation.
Amino acids, 2015Co-Authors: Ine Rombouts, Marlies A. Lambrecht, Sebastien Carpentier, Jan A. DelcourAbstract:The present manuscript reports on the identification of various dehydroamino acid-derived bonds and cross-links resulting from thermal treatment (excess water, 240 min, 130 °C) of two model food proteins, bovine serum albumin, and wheat gliadin. S-Carbamidomethylated tryptic and chymotryptic digests of unheated (control) and heated serum albumin and gliadin, respectively, were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS/MS) with higher-energy collisional dissociation (HCD). Heat-induced β-elimination of cystine, serine and threonine, and subsequent Michael addition of cysteine and lysine to dehydroalanine and 3-methyl-dehydroalanine were demonstrated. Lanthionine, Lysinoalanine, 3-methyl-lanthionine, and 3-methyl-Lysinoalanine were identified. The detection of inter-chain lanthionine in both bovine serum albumin and wheat gliadin suggests the significance of these cross-links for food texture.
Ine Rombouts - One of the best experts on this subject based on the ideXlab platform.
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Identification of lanthionine and Lysinoalanine in heat-treated wheat gliadin and bovine serum albumin using tandem mass spectrometry with higher-energy collisional dissociation.
Amino acids, 2015Co-Authors: Ine Rombouts, Marlies A. Lambrecht, Sebastien Carpentier, Jan A. DelcourAbstract:The present manuscript reports on the identification of various dehydroamino acid-derived bonds and cross-links resulting from thermal treatment (excess water, 240 min, 130 °C) of two model food proteins, bovine serum albumin, and wheat gliadin. S-Carbamidomethylated tryptic and chymotryptic digests of unheated (control) and heated serum albumin and gliadin, respectively, were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS/MS) with higher-energy collisional dissociation (HCD). Heat-induced β-elimination of cystine, serine and threonine, and subsequent Michael addition of cysteine and lysine to dehydroalanine and 3-methyl-dehydroalanine were demonstrated. Lanthionine, Lysinoalanine, 3-methyl-lanthionine, and 3-methyl-Lysinoalanine were identified. The detection of inter-chain lanthionine in both bovine serum albumin and wheat gliadin suggests the significance of these cross-links for food texture.
Michael J. Lynch - One of the best experts on this subject based on the ideXlab platform.
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Structure and chemistry of Lysinoalanine crosslinking in the spirochaete flagella hook
Nature Chemical Biology, 2019Co-Authors: Michael J. Lynch, Michael Miller, Milinda James, Sheng Zhang, Kai Zhang, Nyles W. Charon, Brian R. CraneAbstract:Structural and biochemical characterization of the spirochaete flagellar hook protein FlgE reveals how cysteine and lysine residues spontaneously react to form an interdomain Lysinoalanine crosslink without the involvement of additional enzymes. The flagellar hook protein FlgE from spirochaete bacteria self-catalyzes the formation of an unusual inter-subunit Lysinoalanine (Lal) crosslink that is critical for cell motility. Unlike other known examples of Lal biosynthesis, conserved cysteine and lysine residues in FlgE spontaneously react to form Lal without the involvement of additional enzymes. Oligomerization of FlgE via its D0 and Dc domains drives assembly of the crosslinking site at the D1–D2 domain interface. Structures of the FlgE_D2 domain, dehydroalanine (DHA) intermediate and Lal crosslinked FlgE subunits reveal successive snapshots of the reaction. Cys178 flips from a buried configuration to release hydrogen sulfide (H_2S/HS^−) and produce DHA. Interface residues provide hydrogen bonds to anchor the active site, facilitate β-elimination of Cys178 and polarize the peptide backbone to activate DHA for reaction with Lys165. Cysteine-reactive molecules accelerate DHA formation, whereas nucleophiles can intercept the DHA intermediate, thereby indicating a potential for Lal crosslink inhibitors to combat spirochaetal diseases.
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Spirochaete flagella hook proteins self-catalyse a Lysinoalanine covalent crosslink for motility.
Nature microbiology, 2016Co-Authors: Michael R. Miller, Michael J. Lynch, Sheng Zhang, Kelly A. Miller, Jiang Bian, Milinda E. James, Patrick S. Callery, Justin M. Hettick, Andrew Cockburn, Jun LiuAbstract:Spirochaetes are bacteria responsible for several serious diseases, including Lyme disease (Borrelia burgdorferi), syphilis (Treponema pallidum) and leptospirosis (Leptospira interrogans), and contribute to periodontal diseases (Treponema denticola)(1). These spirochaetes employ an unusual form of flagella-based motility necessary for pathogenicity; indeed, spirochaete flagella (periplasmic flagella) reside and rotate within the periplasmic space(2-11). The universal joint or hook that links the rotary motor to the filament is composed of ∼120-130 FlgE proteins, which in spirochaetes form an unusually stable, high-molecular-weight complex(9,12-17). In other bacteria, the hook can be readily dissociated by treatments such as heat(18). In contrast, spirochaete hooks are resistant to these treatments, and several lines of evidence indicate that the high-molecular-weight complex is the consequence of covalent crosslinking(12,13,17). Here, we show that T. denticola FlgE self-catalyses an interpeptide crosslinking reaction between conserved lysine and cysteine, resulting in the formation of an unusual Lysinoalanine adduct that polymerizes the hook subunits. Lysinoalanine crosslinks are not needed for flagellar assembly, but they are required for cell motility and hence infection. The self-catalytic nature of FlgE crosslinking has important implications for protein engineering, and its sensitivity to chemical inhibitors provides a new avenue for the development of antimicrobials targeting spirochaetes.
Michael Hellwig - One of the best experts on this subject based on the ideXlab platform.
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N-ε-fructosyllysine and N-ε-carboxymethyllysine, but not Lysinoalanine, are available for absorption after simulated gastrointestinal digestion
Amino Acids, 2014Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N -ε-fructoselysine, N -ε-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
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n e fructosyllysine and n e carboxymethyllysine but not Lysinoalanine are available for absorption after simulated gastrointestinal digestion
Amino Acids, 2014Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N-e-fructoselysine, N-e-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
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N-ε-fructosyllysine and N-ε-carboxymethyllysine, but not Lysinoalanine, are available for absorption after simulated gastrointestinal digestion
Amino acids, 2013Co-Authors: Michael Hellwig, René Matthes, Anett Peto, Jürgen Löbner, Thomas HenleAbstract:Food processing leads to a variety of chemical modifications of amino acids in food proteins. Recent studies have shown that some modified amino acids resulting from glycation reactions can pass the intestinal barrier when they are bound in dipeptides. In this study, we investigated as to what extent modified amino acids are released from post-translationally modified casein during simulated gastrointestinal digestion. Casein was enriched with N-e-fructoselysine, N-e-carboxymethyllysine, and Lysinoalanine, in different degrees of modification. The casein samples were subjected to a two-step proteolysis procedure, simulating gastrointestinal digestion. The digestibility of modified casein as measured by analytical size-exclusion chromatography (SEC) decreased with increasing degree of modification especially after enrichment of fructoselysine and Lysinoalanine. Semi-preparative SEC of digested casein samples revealed that fructoselysine and carboxymethyllysine are released bound in peptides smaller than 1,000 Da, which is comparable to native amino acids. The glycation compounds should, therefore, be available for absorption. Lysinoalanine as a crosslinking amino acid, however, is mostly released into longer peptides of at least 30–40 amino acids which should strongly impair its absorption availability.
