Serpins’ Reactive Sites Loops Mobility and Its Functional Value

Abstract

Protein inhibitors from the serpin family are important regulators of various metabolic processes. They differ significantly from most protein inhibitors of proteinases both in structure and in the mechanism of interaction with proteolytic enzymes. The loop of their reactive site is mobile, and the formed complex with enzymes is a covalent acyl-enzyme. Comparison of the properties of serpins both among themselves and with protein inhibitors of other families indicates the key role of the mobility of the loop of the reactive center in ensuring the selectivity of the inhibitors.