Isolation and characterization of a new 36-kDa microfibril-associated glycoprotein from porcine aorta

A new connective tissue protein of 36 kDa has been purified from porcine aorta. The biochemical and immunological properties of the protein are distinct from those of microfibril-associated proteins reported previously such as lysyl oxidase, 31-kDa microfibril-associated glycoprotein, and fibrillin. It could bind to concanavalin A-Sepharose and gelatin-Sepharose. The protein contained the sequence Arg-Gly-Asp-Ala in the amino-terminal region, which is the site for the association with cell and extracellular matrix. Using specific antibody raised to the protein, we demonstrated its restricted localization in aorta adventitia. Immunoelectron microscopy specified its location to a class of extracellular structural elements described as elastin-microfibrils.