US Patent 9290757 Protease screening methods and proteases identified thereby

Methods for identifying modified proteases with modified substrate specificity or other properties are provided. The methods screen candidate and modified proteases by contacting them with a substrate, such as a serpin, an alpha macroglobulins or a p35 family protein or modified serpins and modified p35 family members or modified alpha macroglobulins, that, upon cleavage of the substrate, traps the protease by forming a stable complex. Also provided are modified proteases.