Peptidomic analysis of endogenous and bacterial protease activity in human plasma

The clinical assessment of wound infection and related complications is challenging and the development of objective methods to measure wound status and predict healing outcomes is therefore essential. As endogenous and bacterial protease activities play important roles in healing and infection, analysis of changes in the wound peptidome by individual enzymes could provide insight into proteolytic events occurring in wounds, and may aid in the discovery of biomarkers. We mimicked wound fluid formation and wound infection by digesting plasma ex vivo with endogenous (human neutrophil elastase and Cathepsin G) and bacterial proteases (Pseudomonas aeruginosa LasB and Staphyloccocus aureus V8). Using a peptidomics approach, we characterized the low-molecular-weight peptidome of these samples and identified over 100 protein targets for each enzyme, and found enzyme-specific peptides and digestion patterns.