A unique glycoprotein has been isolated from cultured human embryonic fibroblasts and their culture medium. Analysis showed a composition of 17.5 γ/mg uronic acid, 40 γ/mg hexosamine, and 93.5 γ/mg sialic acid. Gas chromatography revealed fucose, mannose, galactose, and glucose. Ten percent acrylamide 0.1% sodium sulfate acrylamide disc electrophorisis of the glycoprotein after treatment with 6 M urea showed a RF ratio of 0.3 and a molecular weight of about 95,000. The protein content was 454 γ/mg and amino acid analysis revealed high contents of aspartic acid, threonine, glutamic acid, alanine, and leucine.
The existence of acidic glycoproteins in human fibroblasts suggests an association with collagen fibril maturation and may be of etiologic and diagnostic significance in connective tissue disease of the skin.