Isolation of in vivo radiolabeled proteoglycans from rat lung

Sulfated macromolecules of rat lung tissue were labeled in vivo with 35SO 4 and extracted with a solution of 7 m urea containing 0.4% Triton X-100. DEAE-Sephacel chromatography separated sulfated macromolecules into three pools. Pool I consisted of high-molecular-weight, low-density sulfated glycoprotein, probably of mucous secretion origin. Pool II contained a mixture of proteoheparan sulfate and proteodermatan sulfate, together with core protein-free heparan sulfate chains. Pool III was very heterogeneous; its resolution into at least four proteoglycan species was achieved by CsCl density gradient centrifugation. Those included two (high- and low-density) species of proteoheparan sulfate, high-density proteochondroitin sulfate, and medium-density (1.45 < ρ < 1.55 g/ml) proteodermatan sulfate.