Abstract
We discovered cysteine-free and species-specific marker peptides in the whole tryptic digest of animal fibers, which enable rapid identification of cashmere, sheep and yak fibers without pretreatment such as keratin extraction, reduction or reductive alkylation. A simple method for differential identification and quantification of cashmere, sheep and yak in textile products using these marker peptides by liquid chromatography/mass spectrometry (LC/MS) has been developed. The amino acid sequence of each marker peptide was determined by the MS/MS measurement. Each marker peptide was subsequently synthesized and its identity to the peptide from textile samples was confirmed. Commercial textile products were subjected to the measurement with the synthetic peptides as reference markers, and the blending ratios were calculated within an accuracy of 5 ％ compared with the conventional microscopic method.
