BIOC 2580 Lecture Notes - Lecture 4: Globin, Hemoglobin, Nucleophilic Substitution
8 Dec 2017
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Protein structure is very much more complex than any simple organic chemical, but by eliminating detail, a pattern or hierarchy of organization emerges: In centrifugation, a sample is spun in an ultracentrifuge at speeds from 10,000 to 75,000 rpm, producing a force from 10,000 to 500,000 x gravity. At these forces, individual molecules of proteins are large enough to sediment at a rate determined by their size. Electrophoresis is separation based on movement of charged particles in an electric field. A mixture of proteins is placed between a pair of electrodes immersed in a conductive buffer solution, and a voltage of 100 1000 v applied. Positive molecules move towards the negative electrode and negative molecules move to the positive electrode. The rate of movement is a function of size, shape, and charge. See lehninger fig 3 18, p. 89 for an illustration of electrophoresis apparatus.
