Question

please help! I'm just starting peptides this week, so I'm really lost.

Question 1. Consider the small peptide Pro-Cys-Arg-Gln

(a) Draw the entire peptide (careful of peptide bonds!), with charges you would expect on it at pH 7.4. Hint: how many ionizable groups on this peptide?

(b) Tabulate the charge on the molecule at every pH between 1 and 13

(c) Calculate the pI for the peptide.

4. What is the overall charge on the peptide at pH 1? pH 7.4? pH 13?

5. Do you expect this peptide to absorb at 280 nm? Why or why not?

6. Will this peptide form covalent bonds to other peptides in aqueous solution?

7. (g) Mark all the chiral centers in the molecule. How many are there?

Answer 1