BIOL 201 Chapter Notes - Chapter 4: Globular Protein, Electric Field, Molten Globule
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Isoelectric focusing electrophoresis proteins will highest pi value will be at the side with higher ph. Sds page electrophoresis proteins with higher molecular weights migrate through the electric field slower (stays on top of the gel) i. e. smaller polypeptides migrate more rapidly. May retain a 3d structure when separated from the rest of the protein. May be distinct functional units in a protein. Note: both terms describe levels of protein organization more complicated than primary or secondary structure. Christian anfinsen"s ribonuclease a folding experiment (order to produce renaturation of the active protein) : Native state treatment with (cid:537)-mercaptoethanol and 8m urea denatured protein removal of urea and (cid:537)-mercaptoethanol resulting in oxidation of s-h bonds native state. If the urea were removed after the reducing agent was removed i. e. after oxidation occurred, the protein would not refold correctly (less than 5% activity). Disulfide bonds are not positioned correctly unless weak bonding interactions are present.
