Keratin is the main constituent of human skin and can serve as both a target for modifications and an indicator of health. Recent work published in the Journal of Proteome Research explores a non-invasive means to sample keratin and detect its state.
Previously, the authors described mass spectrometry to screen oxidative modifications in human keratin. Their new work improves this approach in terms of sample preparation and amino acid sequencing by using an on-tape digestion method.
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In control and compromised skin groups (i.e., individuals presenting with a red rash), tape-stripping was used to take samples and these were prepared by reduction/alkylation and trypsin digestion without pre-solubilization. The samples were then screened for target modifications, with the control group serving as the reference.
Principal component analysis clearly differentiated both groups, identifying an increase in one modification most significantly present in the patient group. The authors note this method can be used for patient groups to identify different biomarkers of physiological conditions.