Each of the following statements concerning penicillin is correct EXCEPT:

  •  The structure of penicillin resembles that of a dipeptide of alanine, which is a component of peptidoglycan.
  •  An intact β-lactam ring of penicillin is required for its activity.
  •  Penicillin inhibits transpeptidases, which are required for cross-linking peptidoglycan.
  •  Penicillin is a bacteriostatic drug because autolytic enzymes are not activated.