Proteolytic enzymes are found in all life forms, where they catalyze peptide bond hydrolysis during essential biological processes. Proteases of various pathogens have also been shown to use endogenous protease inhibitors to regulate the activity of host proteolytic enzymes encountered during infection. Proteolytic Enzymes and their Inhibitors in Infectious Pathogens brings together key experts to provide a thorough discussion of proteolytic enzymes and their endogenous inhibitors found in parasites, bacteria, and viruses. The book focuses on the respective roles of the different catalytic classes of proteolytic enzymes and their protein-protease inhibitors at the host-infectious organism interface, and how this knowledge may inform drug and vaccine design. Following a foundational overview of proteases and macromolecular inhibitors of pathogenic organisms, authors discuss recent research on distinct classes of proteolytic enzymes in pathogens. Classes include aspartic proteases, cysteine proteases, metalloproteases, serine proteases, and threonine proteases with experts contributing chapters on distinct enzymes and inhibitors. New methods to identify protease substrates and inhibitors are also provided, with step-by-step protocols to advance new research and drive drug discovery.