Pepsin Digestion for Proteomic Studies of the Human Hair Shaft

The study investigates the use of pepsin digestion for proteomic analysis of human hair shafts, addressing discrepancies in keratin ratios observed in previous tryptic studies. Pepsin, which targets hydrophobic and aromatic residues, offers a more accurate representation of keratin ratios and improves protein identification. The research found that pepsin digestion corrected quantitation biases in acidic and basic keratins, aligning with the expected 1:1 stoichiometry, and was more effective in identifying keratin-associated proteins. The study suggests that combining trypsin and pepsin could provide a more comprehensive proteome, with pepsin offering unique advantages in identifying certain proteins, which has implications for health assessments and forensic applications.