Pharmacology The rate-limiting step for nor-epinephrine synthesis is: A Conversion of phenylalanine to tyrosine B Conversion of tyrosine to DOPA C Conversion of DOPA to dopamine D Conversion of dopamine to norepinephrine 💡 Explanation The rate-limiting step for nor-epinephrine synthesis is: ✓ Correct Answer: B. Conversion of tyrosine to DOPA