Iduronic acid-rich proteoglycans (PGIdoA) and human post-burn scar maturation: isolation and characterization

Proteoglycans (PGs) were extracted from human hypertrophic and normal scar tissues from two different stages of maturation after burn injury, under dissociative conditions (4 M guanidinium chloride containing proteinase inhibitors). The extracts were fractionated by ion-exchange chromatography, followed by ethanol precipitation, to give PG-containing iduronic acid (PG IdoA ). The size of the PG IdoA decreased with the maturation of scars. Glycosaminoglycan (GAG) chains from PG IdoA were released by alkaline borohydride treatment, and their M r values were evaluated by polyacrylamide gel electrophoresis. The M r values for PG IdoA protein cores of the hypertrophic scars (5 + years and 2–5 years) and normal scar (5 + years and 2–5 years) were 22.6, 25, 19 and 21 KDa, respectively. The iduronic acid content of PG IdoA from both types of scar increased in their maturation phase. The M r , values of PG IdoA decreased with maturation. PG IdoA carried the sulfate group mainly attached at C-4 of the 2-amino-2-deoxy- d -galactose residue. The NH 2 -terminal amino acid sequences of all the PG IdoA were similar to those of normal human skin or bone PG II (decorin) (i.e., Asp-Glu-Ala-B-Gly-Ile-Gly-Pro-Glu-Val-Pro-Asp-Asp-Arg).