Fig. 6.

In vitro reactivity of pre-β HDL with human LCAT. Individual pre-β HDLs were assembled and isolated (see Fig. 1 legend). An equal amount of pre-β HDL cholesterol (10⁴ dpm) was incubated with 50 ng of purified human recombinant LCAT at 37°C for 1 h (see Methods). The incubation mixtures were then lipid extracted and the percentage of radiolabeled free cholesterol converted to cholesteryl ester was determined. The percentage cholesterol esterification in the absence of added LCAT enzyme (i.e., blank) was measured and subtracted from that measured in the presence of LCAT for each pre-β HDL particle. Results present duplicate incubations, with the horizontal line denoting the average value of the duplicates.