Figure 1.

SV AUC of unfractionated VWF/fVIII complexes. A and B, Heparin-Sepharose purified VWF/FVIII, 0.28 mg/ml in HBS/Ca Buffer was centrifuged at 45,400g in a Beckman-Coulter XLI analytical ultracentrifuge as described in Experimental procedures. The data traces from left to right are scans taken at increasing times during centrifugation. A, absorbance scans at 280 nm. B, interference scans; J, fringe increment. Only every tenth data point of the interference scans is shown for clarity. Curves represent fits to the continuous c(s) distribution model in SEDFIT. The root-mean-square deviations of the fits are 0.0040 and 0.0029 for A280 and interference data, respectively. C, c(s) distributions derived from the fitted data. Red, A280; blue, interference. D, unfractionated VWF/FVIII (red) and bovine serum albumin (black) were centrifuged at 45,400g and 182,000g, respectively, at concentrations ranging from 0.14 to 1.1 mg/ml. s_w values were calculated from c(s) distributions derived from A280 data. s_w values for bovine serum albumin were obtained by integrating the monomer peak of the c(s) distribution (75). The value at infinite dilution, $s_w^0$, was obtained by regression analysis. E–F, VWF/FVIII, 0.55 mg/ml in HBS/Ca Buffer was centrifuged at either 16,400g (15,000 RPM), dotted lines or 45,400g (25,000 RPM), solid lines. E, A280 data, F, interference data.