[Conformational changes of hyaluronic acid in acid medium (author's transl)].

Both vitreous body homogenate and a fibrous product containing hyaluronic acid and collagen isolated from vitreous humor by acetone precipitation were investigated to elucidate the liquefaction of vitreous body by acids. Graphic evaluation of the titration with hydrochlorid acid and viscosity measurements suggest a changed of the hyaluronic acid molecule in the pH-range between 5.2 and 4.1. Between these pH-values the ionization of carboxyl groups is decreased accompanied by conformational changes of the hyaluronic acid molecule. These results are in agreement with the conclusion of other authors that by lowering the pH of hyaluronic acid solutions a random coil to double helix transition of hyaluronic acid occurs.