BIOCHEMISTRY OF THE EYE: II. Gelatinous Protein of Vitreous Body

OF THE proteins which are present in the vitreous body, the gelatinous material seems to be most significant. It has been termed vitrein, 1 or residual protein, 2 and a recent preparation of the structural protein has been called vitrosin. 2 Krause 1 purified the protein by filtration, followed by treatment with papain, and recorded some data on its chemical properties. It was the purpose of this investigation to prepare the gelatinous protein of the vitreous, by methods calculated to preserve its native state as much as possible, and to determine, in part, its chemical composition. METHODS Vitreous bodies from freshly killed cattle were removed and placed on a Buchner funnel without filter paper. Very gentle stirring with a horizontal glass rod allowed the viscous liquid to drain through. About 90% of the original volume was removed, leaving a thick gel. Inevitably, some denaturation occurred during filtration. The opalescent fibers