Studies of alcaptonuria : Mechanisms of swelling of homogentisic acid‐collagen preparations

The effects of solutions of homogentisic acid and its analogues on hide powder collagen preparations have been studied by a volumetric technique. The data indicate that unoxidized homogentisic acid (HGA) reacts reversibly with collagen by pH‐dependent electrovalent forces. Autoxidized, polymerized homogentisic acid solutions (HGA‐OP), on the other hand, form irreversible linkages to collagen which are quite independent of pH. These are primarily of the coordinate, nonionic type and result in crosslinking of adjacent collagen polypeptide chains with increased stability of the collagen lattice (tannage).