The present invention relates to the field of proteases. More specifically, the present invention provides compositions and methods useful for profiling protease activity using phage display. In one embodiment, a display vector useful for profiling protease activity comprises a nucleic acid sequence encoding (a) a peptide to be displayed on the surface of the vector; (b) a first affinity tag C-terminal to the peptide; and (c) a second affinity tag N-terminal to the peptide. The display vector can comprise a virus, bacteriophage, yeast, bacteria, retrovirus, ribosome or mRNA. In particular embodiments, the peptide comprises a human peptidome library peptide.