BIOCH200 Lecture Notes - Lecture 9: Disulfide, Thiol, Carboxamide

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

Document Summary

Biochem 200 - lecture #9 - the amino acids pt. Reactive due to presence of functional groups. Polar amino acids have side chains that contain an electronegative atom. Glycine (gly: achiral (2 functional groups are the same, weakly polar --> coo- and nh3. + are stronger than the h: very small and thus flexible Threonine (thr: polar, uncharged, has 2 chiral carbons, no pka because can"t be protonated unless assisted, hydroxyl group. Typically h-donor (but can be acceptor: can be phosphorylated. Tyrosine (tyr: weakly polar, uncharged, aromatic r group. Hydrophobic interactions (tyr > thr > ser etc: hydroxyl group. Can be phosphorylated: predominant form is charged, can pull off the h of the oh group under basic conditions. Can do this because negative charge can be distributed. Everything is protonated, then the charge would be +1 since cooh is there. Not all r groups have an ionizable r group: uncharged/polar: tyr/his/cys, charged (-): asp/glu, charged (+): arg/lys.