Cathepsin D--a main proteolytic enzyme of the bovine vitreous.

It was found that the bovine vitreous contains a proteolytic enzyme which demonstrates characteristic features of cathepsin D. It acts in acidic pH, actively digests denatured protein substrates and demonstrates a high susceptibility on the inhibitory action of pepstatin. It is localized in liquid part of the bovine vitreous. A role of this enzyme in physiology and pathology of the eye is discussed.