P. Richardin et al., GAS-CHROMATOGRAPHY - MASS-SPECTROMETRY IDENTIFICATION OF COLLAGEN BREAKDOWN PRODUCTS IN NATURALLY AND ARTIFICIALLY AGED LEATHERS, The Journal of the American Leather Chemists Association, 91(1), 1996, pp. 2-17
The purpose of this study is the detection and identification, using c
ombined gas chromatography and mass spectrometry, of breakdown product
s which appear during leather collagen degradation. Experiments were p
erformed on naturally and artificially aged leathers. All gas chromato
grams are similar, with high amounts of the classical amino acids toge
ther with a great number of others at low concentration of which sever
al were identified as: alpha-aminobutyric acid, beta-alanine, pyroglut
amic acid, allo-isoleucine, gamma-aminobutyric acid (GABA), dehydropro
line (dPRO), two isomers of hydroxyproline (cis-3-HYP and cis-4-HYP),
6-aminohexanoic acid, ornithine and alpha-aminoadipic acid (AAD). To e
valuate how much artificial aging affects the release of the breakdown
products, and to compare it to natural aging, semiquantitative and co
mparative analysis were performed on four ''new'' amino acids. We calc
ulated and studied the evolution of the following peaks area ratios: G
ABA/dPRO, cis-4-HYP/trans-4-HYP, dPRO/PRO and AAD/dPRO. Our results co
nfirm the hypothesis that amino acids are first transformed into break
down products in the form of new amino acids, which are then transform
ed into other breakdown products or amino acids.