Predicted to enable serine-type endopeptidase inhibitor activity. Acts upstream of or within response to bacterium; response to cytokine; and response to peptide hormone. Located in extracellular region. Is expressed in several structures, including ganglia; hindbrain; skeleton; thymus primordium; and urinary system. Human ortholog(s) of this gene implicated in adult respiratory distress syndrome; chronic obstructive pulmonary disease; cystic fibrosis; and vasculitis. Orthologous to human SERPINA3 (serpin family A member 3). [provided by Alliance of Genome Resources, Apr 2022]