BIO 361 Lecture Notes - Lecture 4: Isoelectric Point, Specific Activity, Differential Centrifugation
3 Feb 2021
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Classical methods for separating use differences in: If there is a protein that hasn"t been purified yet, multiple types of chromatography need to be done. Salting out is usually first since it is cheaper and gets rid of some contaminants. As each type of procedure is done, the sample volume generally decreases. Proteins are usually found in general tissue or microbial cells b. ) Need to release the proteins into crude extract c. ) this is can be done with differential centrifugation to prepare subcellular fractions of isolate specific organelles. Difference methods can be used to purify the proteins once they are extracted, but one type in particular is commonly used: a. ) Fractionation - using various treatments to separate the proteins into different fractions based on size or charge i. ) ii. ) Uses differences in protein solubility (a complex function of ph, temp, salt concentration, and other factors)
