Amino Acids and Peptides

Structure-Activity Relationship (SAR)

The fundamental biochemical principle stating that a chemical structure dictates its biologic function.

Factors Affecting SAR

Physiochemical properties (hydrophilic/hydrophobic, ionized/non-ionized) and stereochemistry.

Essential Amino Acids

Amino acids that cannot be produced by the body and must be obtained via diet.

Non-Essential Amino Acids

Amino acids that can be synthesized by the cells of the body.

Amino Acid Core Structure

Composed of an amino group, a carboxyl group, a central carbon, and a variable R group.

L vs. D Amino Acids

L-configuration forms proteins in life; D-configuration plays essential roles like in bacterial cell walls.

Glycine

The smallest amino acid, allowing it to fit where others cannot.

Zwitterion

contains both a (+) and (-) charge ions equally of NH3+ and Coo- at the same time, but overall the molecule still has a net charge of 0

Peptide Bond Formation

formed when an amino group attacks a carbonyl group

Peptide Bond Resonance

Electron delocalization that strengthens the bond, requiring 385 kJ/mol total energy to break.

Omega Bond

A peptide bond between two amino acids, it doesn’t rotate easily because resonance gives it some double-bond character. peptide bond makes it rigid and creates an amide plane.

Proline

Features a rigid five-membered ring that constricts the rotation of the Phi bond.