Isolation and characterization of a highly specific serine endopeptidase from an oral strain of Staphylococcus epidermidis

Infection by Staphylococcus epidermidis, an opportunistic pathogen, has bec ome a major problem due to the increased use of implanted medical devices a nd the growing number of patients who are therapeutically or infectiously i mmunosuppressed. These infections appear to proceed via modulation of the c oagulation and complement systems. In this communication we describe the pu rification and characterization of a novel extracellular proteinase from an oral strain of S. epidermidis that can degrade fibrinogen, complement prot ein C5, and several other proteins. This proteinase has a strong preference for cleavage after glutamic acid residues, but not after aspartic acid. Th e S. epidermidis enzyme may be a multifunctional protein which not only pro vides this organism with both the ability to evade the complement defense s ystem and to dysregulate the coagulation cascade, but also supplies nutrien ts for its growth through the degradation of Glu-rich proteins.