MBB 222 Lecture Notes - Lecture 8: Steric Effects, Oligopeptide, Zwitterion
20 Dec 2018
School
Department
Course
Professor
Document Summary
Lecture 8 part 1: proteins - amino acids. Enzymes can change g of a reaction. Enzyme increase both the forward and reverse reaction rates without affecting keq. Lock and key & induced fit models. Polypeptide = large number of aa"s linked by peptide bonds. Oligopeptide = less than 40 aa"s linked by peptide bonds. Residue = aa or nucleotide depending on context. Zwitterion = neutral molecule with both positive and negative charges. 20 different possibilities for each position if there are 10 positions to fill, Most proteins are much longer than 10 residues. Gly, ala have the least steric hindrance (don"t interfere with backbone bond rotation) Gly in particular imparts flexibility in the peptide backbone due to the absence of a side chain. Aliphatic (hydrophobic, non-polar) side chains from alanine to methionine, the r groups increase in size and their hydrophobicity increases; the more hydrophobic amino acids are usually buried within the protein molecule, so that they don"t contact water.
