Serine protease inhibitor A3C (Serpin A3C)

Serpina3c, full name serine (or cysteine) peptidase inhibitor, is a serine protease inhibitor (Serpin). Serpina3c is an extracellular secreted protein that is mainly expressed in white adipose tissue (WAT), brown adipose tissue (BAT), heart, brain, pancreas, and lung, with lesser expression in liver, skeletal muscle, spleen, and kidney.The Serpin A3C protein has a reaction center ring (RCL) protruding from its main body that guides it to interact with the target protease. After binding, the protease cleaves the serine protease inhibitor at the reaction site within the RCL to form a persistent and covalent serine protease inhibitor-protease complex. The complex was marked by protease inactivation and showed remarkable stability. Different sequences within the RCL of Serpina3 orthologues lead to variability that may affect the specificity of target protease interactions.