HIGH-DENSITY LIPOPROTEIN BINDING TO GUINEA-PIG HEPATIC MEMBRANES - COMPARISON OF GUINEA-PIG AND HUMAN LIGANDS

Human and guinea-pig apo-E-free HDL were incubated with isolated guinea-pig hepatic membranes at 4 and 37 °C to determine the effects of temperature and heterologous systems on the equilibrium parameters of HDL binding. Receptor mediated HDL binding was highest at 37°C for both lipoproteins. At 4°C, a higher affinity constant (Kd) was observed when guinea-pig HDL was the ligand relative to human HDL; in contrast, both HDL preparations had similar Kd values at 37°C. Calculated binding and receptor number (Bmax) were higher at both temperatures when guinea-pig HDL was the ligand. These results demonstrate a significant species difference in HDL binding to hepatic membrane which is partially temperature-dependent. © 1990.