A parallel between two techniques of extraction of connective tissue macromolecules

Abstract

A method of extraction of the collagen and noncollagen proteins from deep dermis of young adult rabbits using a 0.1 m tartaric acid solution was set up. The tartaric acid extraction, together with the preliminary neutral salt extraction, solubilized 95% of the total collagen and 98% of the noncollagen proteins, far more than the 6 m guanidinium Cl solution used for comparison. Elastin was not extracted. Studies on the fibrillation of the extracted collagen in neutral solution at 25°C or on the results of pepsin digestion in acidic solution at +4°C showed that the tartaric acid-extracted collagen was in a nondenatured form, whereas that extracted by guanidinium Cl was largely denatured. Polyacrylamide gel electrophoresis (PAGE) indicated that most of the collagen was of type I and that many noncollagen proteins were present, mostly in the molecular weight range of 40 kDa. Bidimensional PAGE gave a reproducible pattern of these noncollagen proteins, showing that several additional proteins were present in tartaric acid extracts and not in guanidinium chloride extracts.