Papaʹs got a brand new tag: advances in identification of proteases and their substrates

Characterization of proteolytic enzymes and their substrates presents a formidable challenge in the context of biological systems. Despite the fact that an estimated 2% of the human genome codes for proteases, only a small fraction of these enzymes have well-characterized functions. Much of the difficulty in understanding protease biology is a direct result of the complexity of regulation, localization and activation exhibited by this class of enzymes. Here, we focus on several recently developed techniques representing crucial advances toward identification of proteases and their natural substrates.