This protein strongly inhibits papain and ficin, partially inhibits stem bromelain and bovine cathepsin C, but does not inhibit porcine cathepsin B or clostripain. Papain is inhibited non-competitively.
Subcellular locations: Secreted
Expressed in submandibular and sublingual saliva but not in parotid saliva (at protein level). Expressed in saliva, tears, urine and seminal fluid.