Tuftsin Is a Peptide That Stimulate and Promotes the Destruction

Multiple Choice

Tuftsin is a peptide that stimulate and promotes the destruction of tumor cells. Its primary structure is Thr-Lys-Pro-Arg. Which statement is NOT a valid interpretation of its primary structure?

A) It is a tetrapeptide.
B) Threonine is the N-terminal amino acid and arginine is the C-terminal amino acid.
C) The amino group of arginine is not joined to any other amino acid.
D) The carboxyl group of lysine is joined to the amino group of proline.