Contributes to serine-type endopeptidase inhibitor activity. Involved in negative regulation of interleukin-1 beta production. Acts upstream of or within regulation of protein catabolic process. Predicted to be located in cytoplasmic ribonucleoprotein granule and extracellular region. Predicted to be active in extracellular space. Is expressed in several structures, including alimentary system; brain; dorsal grey horn; naris; and physiological umbilical hernia dermis. Orthologous to human SERPINB1 (serpin family B member 1). [provided by Alliance of Genome Resources, Apr 2022]