The amino-terminal region of a proteochondroitin core protein, secreted by aortic smooth muscle cells, shares sequence homology with the pre-propeptide region of the biglycan core protein from human bone
Marcum, J.A.; Thompson, M.A.
Biochemical and Biophysical Research Communications 175(2): 706-712
1991
ISSN/ISBN: 0006-291X PMID: 2018513 Document Number: 377559
Smooth muscle cells, isolated from rat and bovine aortae ang grown in vitro, synthesize chondroitin sulfate proteoglycans which are secreted into the growth media. Analysis of metabolically [35S]-labeled macromolecules, employing ion-exchange chromatography, revealed a single peak of radioactivity, upon elution with a linear salt gradient. Treatment of the material with enzymes that specifically degrade chondroitin sulfate demonstrated that chondroitin-4-sulfate was the predominant species isolated from rat smooth muscle cells and that chondroitin-4-sulfate and dermatan sulfate were the predominant species isolated from bovine aortic smooth muscle cells. Treatment of the native proteoglycans with chondroitinase ABC and subsequent SDS-PAGE analysis of the digestion products resulted in the appearance of a band with an apparent molecular weight of 45,000. Electrotransfer of the core protein to Immobilon-P membrane and gas phase sequenching of the amino-terminal region revealed striking homology between the core proteins of the rat and bovine proteochondroitin with the pre-propeptide region of human bone biglycan.