BCMB20005 Lecture Notes - Lecture 8: Molecular Sieve, Carboxymethyl Cellulose, Thrombin
2 Aug 2018
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Document Summary
Bacterial cell that contain our overexpressed protein. Cheap , quick process that remove proteases, use column chromatography. Low capacity of volume can be added to the column in the starting material. Ionic strength increase, solubility decrease: salts can selectively precipitate proteins (e. g. ammonium sulfate. (nh 4 ) 2 so 4 - highly soluble and readily available. Can also be used to concentrate dilute proteins: removed protein from those remaining in solution by precipitation and low speed centrifugation. High [salt] removes hydration shell from around protein exposes hydrophobic patches on protein surface. Water solvates proteins forms hydration shell (weak interaction) Polar/ionisable residues of protein interact with h 2 o through dipoles (weak. Most hydrophobic amino acid residues are found within folded proteins, but interaction) some found on surface. At hydrophobic patches, water forms ordered structure specific van der waals interactions with the protein. Result: water is weakly bound at hydrophobic patches. Exposed hydrophobic patches on protein interact -> form protein aggregates.
