title: Modification of collagen in vitro with respect to formation of Nepsilon-carboxymethyllysine.
abstract: Developing new biopolymer-based materials with bio-identical properties is a significant challenge in modern science. One interesting route to this goal involves the biomineralization of collagen, a pre-structured and widely available protein, into a material with interesting properties. A prerequisite for biomineralization is the ability of cations (e.g., calcium) to bind to the protein and to result in concert with appropriate anions (e.g., phosphate) in composite material with e.g., bone-like properties. In order to increase the number of binding sites it is necessary to modify the protein prior to mineralization. For this glucuronic acid (GA) was used due to its carbonyl and carboxyl groups to derivatize proteinogenic amino groups transferring them into negatively charged carboxyl groups. Our experiments showed for the first time, that Nepsilon-carboxymethyllysine is the major product of in vitro non-enzymatic glycosylation of collagen by glucuronic acid. For an unequivocal determination of the reaction products, the lysine residues of collagen and of the model peptide were carboxymethylated through a reductive alkylation with glyoxalic acid and compared to the glucuronic acid derivatives. Beside their identical mass spectra the common structure elements could be confirmed with FTIR. Thus, in the context of matrix engineering, by producing Nepsilon-carboxymethyllysine, glucuronic acid offers a convenient way of introducing additional stable acidic groups into protein matrices.
authors.affiliation: Max Bergmann Centre of Biomaterials, Institute of Materials Science, Technische Universität Dresden, 01069 Dresden, Germany. Hermann.Ehrlich@tu-dresden.de
authors.forename: Hermann
authors.initials: H
authors.lastname: Ehrlich
authors.forename: Thomas
authors.initials: T
authors.lastname: Hanke
authors.forename: Andrej
authors.initials: A
authors.lastname: Frolov
authors.forename: Tobias
authors.initials: T
authors.lastname: Langrock
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
authors.forename: Christiane
authors.initials: C
authors.lastname: Fischer
authors.forename: Uwe
authors.initials: U
authors.lastname: Schwarzenbolz
authors.forename: Thomas
authors.initials: T
authors.lastname: Henle
authors.forename: René
authors.initials: R
authors.lastname: Born
authors.forename: Hartmut
authors.initials: H
authors.lastname: Worch
mesh_terms: D000596:Amino Acids / Q000032:analysis; D032701:Biomimetics / Q000379:methods; D001704:Biopolymers / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry*; D008239:Lysine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D013058:Mass Spectrometry; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000596:Amino Acids; D001704:Biopolymers; C048496:N(6)-carboxymethyllysine; D020723:Glucuronic Acid; D003094:Collagen; D008239:Lysine