1. Spectrophotometry

A) Calculate the extinction coefficients at 280 nm (in units of M-1 cm-1) of the 4 peptides below. You can use an online tool to do so; e.g. enter the sequence into https://web.expasy.org/protparam/Links to an external site..

1) KENDREW 2) DARWIN 3) FARADAY 4) FRANKLIN

B) Why are the extinction coefficients different for the 4 peptides?

C) What equation do you think the online calculator uses for calculating the peptides' extinction coefficients?

D) What would be the concentration of a solution of peptide 1, if you measure A₂₈₀ = 0.75, using a spectrophotometer with a 1 cm path length? Use the Beer-Lambert law. (The subscript in A₂₈₀ means that A is measured at 280 nm.)

Need help on D only****