Question: Draw both enantiomers of each amino acid and label them as Ror S:(a) phenylalanine; (b) methionine.

Phenylalanine has the molecular formula ${\mathbf{C}}_{\mathbf{9}}{\mathbf{H}}_{\mathbf{11}}{\mathbf{NO}}_{\mathbf{2}}$. It has several isomers, one of which is D-phenylalanine.

Methionine is an essential amino acid comprising sulfur atoms. It is utilized to cure liver disorders.

The groups connected to the stereocenter are prioritized to determine the stereochemistry of a compound. The groups with a higher atomic number are given greater priority than those with a lower atomic number.

A compound is assigned R configuration if it rotates in the clockwise direction and is assigned S configuration if it rotates in the anticlockwise direction.

(a) The enantiomers of phenylalanine are given below:

Enantiomers of phenylalanine

(b) The enantiomers of methionine are given below:

Enantiomers of methionine