Enables serine-type endopeptidase inhibitor activity. Acts upstream of or within several processes, including negative regulation of cellular protein metabolic process; negative regulation of nitric oxide mediated signal transduction; and regulation of calcium ion transport. Located in extracellular space. Is expressed in embryo ectoderm; embryo endoderm; genitourinary system; gut; and yolk sac. Human ortholog(s) of this gene implicated in pancreatitis. Orthologous to human SPINK1 (serine peptidase inhibitor Kazal type 1). [provided by Alliance of Genome Resources, Apr 2022]