FOOD 2400 Lecture Notes - Lecture 9: Isoelectric Point, Amine, Amphoterism

• School: University of Guelph
• Department: Food Science
• Course: FOOD 2400
• Professor: Yoshi Mine

Document Summary

4 classes according to polarity of r- side chains which relate to the acid-base properties of amino acids: non-polar or hydrophobic side chains, polar-uncharged (hydrophilic) side chains. 8 essential amino acids for adult humans: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The human infant also requires histidine: give examples of simple, derived, and conjugated proteins? (protein classes), 7 classes of simple proteins based on solubility are: Conjugated proteins contain both an amino acid and a non-protein moiety. Primary : linear sequence of amino acids via peptide bonds determines it. How it fold upon itself, backbone interactions stabilized by h-bonds. Tertiary: three dimensional organization of a polypeptide chain , higher order of folding of the various secondary structures. Hydrogen bonds, van der waals forces, disulfide bridges, and hydrophobic interactions stabilize tertiary structures. Irradiation: uv radiation absorbed by aromatic amino acid residues and results on modified conformation. disulfide cross-links may are ruptured if energy is sufficient.