MBB 222 Lecture Notes - Lecture 8: Aromatic Amino Acids, Guanidine, Imidazole
20 Dec 2018
School
Department
Course
Professor
Document Summary
Lecture 8 part 2: proteins - amino acids. Are bulky, hydrophilic ( water- loving ) Usually found on the surface of proteins, exposed to aqueous environment. Positively charged at or near neutral ph (physiological conditions) contribute to the overall charge of proteins. Histidine has an imidazole group - can be protonated or deprotonated at or near neutral ph good buffer lysine has an amino group at the end of the side chain. Lys and arg are protonated at neutral ph (positively charged) Acidic amino acids and their amides the side chains of aspartic acid and glutamic acid have a carboxylate group. Are negatively charged at physiological ph (aspartate and glutamate refer to the ionized forms) Asparagine and glutamine are the amide forms of aspartate and glutamate are uncharged but hydrophilic due to polar carboxamide (amide) groups. Amide/carboxamide groups can participate in h bonds. Asp, glu, asn, gln are bulky, hydrophilic amino acids.
