Sedimentation velocity profile of apoHuHF. Curves a, b and c correspond to the addition of 0, 1 and 5 mM DTT to the protein and demonstrate the presence of disulfide linkages. Inset: Fitting of 5 mM DTT sample (curve a of main figure) to the sum of two Gaussian functions with the parameters: A1 = 0.9272 ± 0.0007, speak,1 = 16.59 ± 0.002 S, σobs,1 = 2.66 ±0.01 S, A2 = 0.1312 ± 0.0019, speak,2 = 23.9 ± 0.1 S, σobs,2 = 2.8 ± 0.1 S and y0 (offset) = 0.0519 ± 0.0008 with reduced χ2 = 0.00002 and R2 = 0.99588.