Purification and characterization of a poly-L-lysine-activated serine endoprotease from Lumbricus rubellus

An endoprotease in earthworm (Lumbricus rubellus) is purified to apparent homogeneity using 125I-lactalbumin as a substrate. The protease has a molecular mass of 27 kDa and is markedly activated by poly-L-lysine or poly-L-arginine. It is a chymotrypsin-like serine protease. Its activity is distributed to coelomic fluid but relatively little to coelomocytes.