Amino Acids

Question 1

When do amino acid exist as zwitterions?

Answer 1

• At a pH value called the isoelectric point.

* R groups can determine the value of the isoelectric point. Acidic : decrease the IEP; basic: increases the IEP.

Question 2

What are optical isomers?

Answer 2

• Non superimposable mirror images about the chiral centre.
• Optical isomers and E/Z isomerism are different types of stereoisomers : have the same structural formula, but different arrangement of atoms in space.
• Two compounds that are optical isomers of each other are called enantiomers.

Question 3

What is the synthesis of a pharmaceutical?

Answer 3

• Is a single isomer.
• There’s an increased cost due to the difficulty in separating the optical isomer.
• There’s a reduction in possible side effects; thus increased pharmacological activity.

Question 4

How is modern synthesis of a pharmaceutical with a single isomer carried out?

Answer 4

• Using enzymes or bacteria to promote stereoselectivity
• Using chemical chiral synthesis or chiral catalysts
• Using natural chiral molecules, like L- amino acids and sugars as starting materials.

Question 5

What are amino acids?

Answer 5

• They’re amphoteric - have basic (NH3) and acidic properties (COOH).
• General formula for a amino acids- RCH(NH2)COOH.