The binding of human aortic glycosaminoglycans and proteoglycans to plasma low density lipoproteins

Abstract

The interaction of glycosaminoglycans and proteoglycans with low density lipoproteins has been studied. Aortic and cartilaginous glycosaminoglycans are retained in LDL affinity columns and produce turbidity when added to LDL in presence of Ca2+. When extracted from whole aortic walls, dermatan sulfate is the glycosaminoglycan that shows greatest affinity for LDL. However, when using the glycosaminoglycans obtained by papain hydrolysis of the proteoglycans extracted from aorta, the binding affinity with LDL was similar for dermatan sulfate and chondroitin 4/6-sulfate. Removal of the protein core of the aortic or cartilaginous proteoglycans did not prevent interaction with LDL. However, treatment with testicular hyaluronidase abolished totally such interaction. When aortic glycosaminoglycans and proteoglycans were applied to LDL affinity columns in presence of Ca2+, a marked increase in the average molecular weight of the glycans found in the eluates of higher NaCl concentration was observed. This result suggests that the molecular weight of the glycosaminoglycans is a relevant factor for the binding of these compounds to LDL.