[Analysis of the hydroxyproline containing serum proteins in connective tissue diseases (author's transl)].

The serum proteins were fractionated on Sephadex G 200, their hydroxyproline content determined. Three protein peaks (I-III) containing different hydroxyproline concentrations could be separated. In connective tissue disorders accompanied by increased collagen synthesis or collagen degradation, an elevation of hydroxyproline was found in peak II. An increase of hydroxyproline always was associated with an increase of the serum proteins in the same fractions. Hydroxyproline serum levels above normal obviously are due to a certain capacity of the serum proteins binding free hydroxyproline and collagen metabolites.