Inhibitor of serine proteases. Has moderate inhibitory activity for trypsin-like peptidases, but also some activity with cysteine peptidases, cathepsin L, K, and V, and the serine peptidase, tryptase gamma. Expressed in eye, lung, lymphocytes, thymus, stomach, uterus, heart, brain, liver, skeletal muscle, and in day 7, 15, and 17 embryos. Belongs to the serpin family. Ov-serpin subfamily.