Enables serine-type endopeptidase inhibitor activity. Involved in protein catabolic process. Located in cell surface; extracellular space; and intracellular membrane-bounded organelle. Biomarker of calcium oxalate nephrolithiasis. Human ortholog(s) of this gene implicated in acute kidney failure and adult respiratory distress syndrome. Orthologous to human AMBP (alpha-1-microglobulin/bikunin precursor). [provided by Alliance of Genome Resources, Apr 2022]