The invention relates to a method for isolating from connective tissue a variety of glycosaminoglycan (GAG)-polypeptide complexes and polypeptides which are substantially free of contaminating DNA and other molecules such as viruses which may be associated with the DNA in the cell. The invention also relates to uses of GAG-peptide complexes and polypeptides substantially free of DNA either directly, or after further processing, for the treatment, protection and restoration of connective tissues in inflammatory and degenerative disorders such as rheumatoid arthritis and osteoarthritis in any of their multiple forms or other degenerative conditions in mammals.