Hemolymph. The reactive center loop (RCL) extends out from the body of the protein and directs binding to the target protease. The protease cleaves the serpin at the reactive site within the RCL, establishing a covalent linkage between the serpin reactive site and the active site of the protease. The resulting inactive serpin-protease complex is highly stable (By similarity). The N-terminal section (1-336) is identical to the N-terminal section of the silk moth antitrypsin I (17-352). Belongs to the serpin family.