Heparan sulfate of skin fibroblasts grown in culture.

Primary cultures of normal human skin fibroblasts were examined for glycosaminoglycan content. Heparan sulfate was found in the growth medium of these cells, in fractions obtained by sequential collagenase and trypsin treatments, and in the remaining intact cells. Heparan sulfate was found to be the major sulfated glycosaminoglycan of the trypsin fraction but appeared as a smaller proportion of the collagenase fraction. The heparan sulfate of the growth medium, the collagenase fraction, and the trypsin fraction appeared to be proteoglycan while intracellular material appeared to be mainly free polysaccharide. The collagenase fraction is thought to be representative of "matrix" material produced by the cells, while the trypsin fraction may represent external cell surface material. The trypsin fraction heparan sulfate polysaccharide was relatively homogeneous in size with an average molecular weight of approximately 40,000 relative to a chondroitin sulfate standard. It was also relatively homogeneous in sulfate content, containing an average of 0.8 sulfate groups per disaccharide repeating unit. Approximately 50% of this was N-sulfate.