A new protein namely protein X has been isolated by molecular biologists. The protein is shown to have a spherical shape and a radius of 12 nm. Before they could measure its diffusion coefficient at 25°C, their device breaks. However, they have data from a previous measurement taken using the same device, at 25°C which showed diffusion coefficient of albumin (spherical with R=3 nm, M= 68,000 g/mol) to be 6.8x10-7 cm2/s. Determine the diffusion coefficient of protein X

A protein has a molecular mass of 400 kDa when measured by size-exclusion chromatography. When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecular masses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol, three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein and clearly explain how you came to this determination.

The extinction coefficient or absorptivity (ɛ) of protein A at 340 nm is 6440 M-1 cm-1, whereas protein B does not absorb at 340 nm. What absorbance will be observed when light at 340 nm passes through a 5 mm cuvette containing 10 µM of protein A and 10 µM of protein B? Beer-Lambert-law; A = ɛ x C x1; A = absorbance, C= concentration, 1= pathlength).

Figure 3: ● ● ● ● ● ● KDa ● 97.4 66.2 45.0 ● 31.0- 21.5 14.4 S-1 p-1 S-2 2-0 This figure was generated by centrifuging a pura sample of protein, removing the supernatant, and resuspending the pellet in the same volume as the supernatant to allow direct comparison. The supernatant and pellet samples were then prepared for SDS-PAGE identically and run via normal SDS-PAGE procedures. In the figure, "s" means supernatant and "p" means pellet. The text or number after the dash represents a different condition. For example, s-1 and p-1 are the supernatant and pellet samples under condition 1. It is not shown, but under wild-type conditions, essentially all of the protein is found in the supernatant. S-3 ● What does the intensity of each band represent? ● Would you find soluble protein in the supernatant or pellet? Why? Would you find aggregated protein in the supernatant or pellet? Why? For each condition (there are 5 different conditions), is there a higher percentage of the total protein…