CHEM237 Lecture Notes - Lecture 7: Peptide Bond, Electric Field, Chromophore
30 May 2017
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Peptide bond: condensation formed by cooh of one and nh3 of other= hydrolysis (<30aas), nucleophilic attack on the carbonyl c. When calculating pi"s of peptides, us the average pka values on the end side chains. In a polypeptide chain, the c-n has partial double bond characters but there is rotation around the bond (which is restricted) Can be cis or trans but most are trans. If you know the gene sequence, you know the protein sequence, proteins, charges, etc. (design purification parameters accordingly) Solubility: add salts (ammonium sulfate, nacl) causes proteins to stick together which can be centrifuged out. Thermostable: stays folded when boiled while others unravel into solution. Certain amino groups affect size, charge, and hydrophobicity by its characteristics. 1: do an assay (to detect presence of protein) 3: at certain wavelengths, you can test for absorbance as proteins have different absorptivity/molar extinction coefficients (no proteins = no absorbance)
