title: Introduction of new crosslinks into proteins.
abstract: Analysis of the crosslinks epsilon-(gamma-glutamyl) lysine and epsilon- (beta-aspartyl) lysine present in treated wool has been improved by modifying the enzymic digestion. Treatment of wool with either monocarboxylic acid chlorides in dimethylsulfoxide or with 1-fluoro-2,4-dinitrobenzene in the presence of acetate considerably decreased epsilon-amino groups and solubility. Since no information of interchain amide crosslinks was observed, the hypothesis of so-called self-crosslinking postulated by ZAHN has to be withdrawn. The effects of both treatments are explained in the light of new results. The reaction of wool with glutaraldehyde leads to a stabilization of the fiber. Experiments with glutaraldehyde and  primary alkyl amines as model componds revealed that the cyclic form of the aldehyde gave the unstable N-alkyl-2,6-dihydroxypiperidine, which either looses water to give N-alkyldihydropyridine or condenses with 2,6-dihydroxytetrahydropyran to yield a copolyether which was isolated. According to recent publications, crosslinking of proteins by glutaraldehyde is due to the formation of quaternary pyridinium compounds.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001224:Aspartic Acid; D055598:Chemical Phenomena; D002621:Chemistry; D004140:Dinitrophenols; D005971:Glutamates; D005976:Glutaral; D007202:Indicators and Reagents; D007633:Keratins; D008239:Lysine; D046911:Macromolecular Substances; D011487:Protein Conformation; D013696:Temperature; D014935:Wool
chemical_list: D000596:Amino Acids; D004140:Dinitrophenols; D005971:Glutamates; D007202:Indicators and Reagents; D046911:Macromolecular Substances; D001224:Aspartic Acid; D007633:Keratins; D008239:Lysine; D005976:Glutaral