Draw the product obtained when a lysine side chain in a polypeptide reacts with maleic anhydride.

For each compound,

1. name the functional group.

2. show what compound(s) result from complete hydrolysis.

(c)

a. Calculate the overall yield of bradykinin when the yield for the addition of each amino acid to the chain is 70%.

b. What would be the overall yield of a peptide containing 15 amino acids if the yield for the incorporation of each is 80%

What dipeptides would be formed by heating a mixture of valine and N-protected leucine?

Proof that an imine was formed between aldolase and its substrate was obtained by using D-fructose-1,6-bisphosphate labeled at the C-2 position with ¹⁴C as the substrate. NaBH₄ was added to the reaction mixture. A radioactive product was isolated from the reaction mixture and hydrolyzed in an acidic solution. Draw the structure of the radioactive product obtained from the acidic solution. (Hint: NaBH₄ reduces an imine linkage.)

Draw the tetrapeptide Ala-Thr-Asp-Asn and indicate the peptide bonds.

The unique properties of the 20 common amino acids are determined by which of the following?

How many different amino acids are commonly found in proteins?