BIOCH200 Lecture Notes - Lecture 1: Side Chain, Zwitterion, Amine

• School: University of Alberta
• Department: Biochemistry
• Course: BIOCH200
• Professor: Jonathan Parrish

Document Summary

The amino acids and the properties of their side chains. The figure shows the structure of a general amino acids at ph 7. It has one hydrogen attached to the a- carbon, one carboxylate group and one amino group. It is a neutral ion with both positive and negative (cid:272)harges, he(cid:374)(cid:272)e it(cid:859)s a zwitterio(cid:374). The r group is what makes each amino acid unique. Longer side change hence more hydrophobic than alanine. At ph 1, it is called aspartic acid. As pka< ph it has 2 cooh groups. Charged amino acids: negatively charged r group at ph 7, very polar, forms hydrogen bonds, h bond acceptor, at ph 7 it is called glutamic acid, pka= 4. 0. Very polar pka= 10. 0: positively charged side group at ph 7, guanido group, never deprotonated under physiological conditions, forms hydrogen bonds, h bond donor, pka= 12. 5, very polar. If ph is less than pka, the amino acid has a positive charge.