Interaction of prostaglandins with blood plasma proteins. Comparative binding of prostaglandins A2, F2α and E2 to human plasma proteins

[摘要]

1. The binding of prostaglandin A₂ and prostaglandin F_2α to human plasma proteins was investigated by DEAE-Sephadex chromatography and polyacrylamide-gel electrophoresis. Both prostaglandins, when added to human plasma in vitro, were found to become bound mainly to plasma albumin. 2. The extent of binding of prostaglandins added to human plasma in low to moderate concentrations was found to be approx. 88, 73 and 58% for prostaglandins A₂, E₂ and F_2α respectively. The order of affinities for the binding of the three prostaglandins to albumin appear to be A₂>E₂>F_2α. 3. The apparent association constants for the binding of these prostaglandins to human serum albumin were estimated to be approx. 4.8×10⁴, 2.4×10⁴ and 0.9×10⁴ litre/mol for prostaglandins A₂, E₂ and F_2α respectively. The results are compared with previously reported association constants for the binding of long-chain fatty acids to both human and bovine albumins.