Enables complement binding activity and serine-type endopeptidase inhibitor activity. Predicted to be involved in negative regulation of complement activation, lectin pathway and negative regulation of endopeptidase activity. Predicted to act upstream of or within several processes, including complement activation, classical pathway; fibrinolysis; and negative regulation of peptidase activity. Located in extracellular space. Is expressed in several structures, including genitourinary system; neural ectoderm; notochord; pancreas mesenchyme; and visceral pericardium. Human ortholog(s) of this gene implicated in several diseases, including COVID-19; angioedema (multiple); cerebral infarction; pancreatitis; and toxic shock syndrome. Orthologous to human SERPING1 (serpin family G member 1). [provided by Alliance of Genome Resources, Apr 2022]