Predicted to enable serine-type endopeptidase inhibitor activity. Acts upstream of or within response to cytokine and response to peptide hormone. Predicted to be located in extracellular region. Predicted to be active in extracellular space. Is expressed in axial skeleton tail region; ganglia; hindbrain; and thymus primordium. Human ortholog(s) of this gene implicated in 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]