This gene encodes a fusion protein that undergoes proteolytic processing to generate two mature proteins: alpha-1-microglobulin (A1m) is a heme-binding plasma glycoprotein of the lipocalin superfamily of proteins that bind to hydrophobic molecules, whereas bikunin belongs to the superfamily of Kunitz-type protease inhibitors. The transgenic mice specifically lacking bikunin, but not A1m, exhibit female infertility and an increased sensitivity to lung metastasis. [provided by RefSeq, Oct 2015]