CHEM237 Lecture Notes - Lecture 3: Hydroxyproline, Glutathione Disulfide, Isoelectric Point

• School: University of Waterloo
• Department: Chemistry
• Course: CHEM237
• Professor: Elisabeth Daub

Document Summary

There are 20 protein amino acids that are called alpha amino acids because the r is on the alpha carbon. The carbon next to the carbonyl group is called the alpha carbon, then the b carbon, and then the y carbon. The neutral form of amino acids has nh2 (base with ph = 9. 5) and cooh (acid with ph. = 2. 2) but the zwitterionic form is the form that we will be drawing. Amino acids undergo an internal acid-base reaction and form a zwitterionic form at physiological ph, where the ph = 7 generally. Amino acids can thus act as an acid or a base because of both groups. 20 amino acid structures and their side chain pkas, and only the amino acids with dissociable protons in their side chains have this pka value. Each amino acid has a characteristic pka value for the alpha amino and alpha-carboxyl group.