Mass Spectrometry Biomarker Quantification in Processed Cashmere Yarns
LC-MS/MS proteomic quantification isolates species-specific tryptic peptides to measure cashmere content in processed yarns within two percent accuracy.
Peptide Deamidation
Chemical Alteration
Chemical modifications in protein based fibres involve the conversion of specific amino acid side chains into different functional groups. Scientists study peptide deamidation to understand how silk and wool age over time when exposed to light or heat. This change alters the net charge and stability of the protein structure.
Molecular Mechanism
Asparagine and glutamine residues lose an amine group and transform into aspartic or glutamic acid. This peptide deamidation occurs more rapidly in alkaline environments or under high thermal stress during processing. The reaction introduces a negative charge that can affect how the fibre accepts dye molecules.
Physical Consequence
Brittleness and loss of luster often follow the accumulation of these chemical shifts in the fibre cortex. Because peptide deamidation breaks the original sequence of the protein, it can create weak points where the yarn is likely to snap. Finished fabrics lose their soft hand and become prone to abrasion damage.
This process eventually leads to the fragmentation of the material.
Aging Assessment
Advanced liquid chromatography and mass spectrometry detect the slight weight changes associated with this reaction. Measuring the extent of peptide deamidation allows conservators and quality experts to determine the remaining lifespan of high value antique textiles. It provides a molecular clock for the degradation of natural fibres.