Protein from complex mixtures

McDonald, W.H., Ohi, R., Miyamoto, D.T., Mitchison, T.J., Yates, J.R. (2002). Comparison of three directly coupled HPLC MS/MS strategies for identification of proteins from complex mixtures single-dimension LCMS/MS, 2-phase MudPIT, and 3-phase MudPIT. Int J. Mass Spectrom. 219, 245-251. 

With the advent of HPLC, a new tool was born that revolutionized peptide/protein chemistry as a whole as it allowed not only purification of biologically active peptides and proteins from complex mixtures of tissue or plant extracts/231 but also allowed purification of synthetic unprotected peptide mixtures analytically and preparatively.124-261 This was particularly significant in that purity could be assessed of peptide intermediates made by the classical solution-phase methodology that promoted characterization of all intermediates, as well as the purity of final products made by the solid-phase approach of MerrifieldJ27 ... 

Although the case just presented focused on the isolation of molecules and proteins from complex mixtures found or derived from nature, the same principles can also... 

Small scale preparative work is important for recovering valuable products like recombinant proteins from complex mixtures. Because of its high resolving power, preparative scale liquid chromatography (LC) has moved rapidly into the biotechnology industry where it is used for purifying such... 

Macfarlane, D.E. (1989) Two dimensional benzyldimethyl-n-hexadecylaimnonium chloride-sodium dodecyl sulfate preparative polyacrylamide gel electrophoresis a high capacity high resolution technique for the purification of proteins from complex mixtures. Anal. Biochem. 176,457-463. 

Protein beads, chips, and/or other affinity-based supports represent an important emerging technology for the separation of proteins from complex mixtures and/or for the examination of specific protein-protein interactions. For example, protein chips consist of arrays of small spots on a solid support (e.g., aluminum, glass, etc. plate), with each spot containing a protein capture moiety or bait, either chemical... 

The soluble proteins are precipitated from aqueous solutions by a large number of salts. These salts may be divided into two classes, namely, those, such as sodium chloride and ammonium sulphate, which precipitate (salt out) the protein in an unchanged condition, and those which form insoluble compounds with the protein, such as the salts of copper and silver. Salting out is an important means of separating proteins from complex mixtures obtained from animal and plant tissues and from one another, and has been the subject of much investigation. The salts which precipitate proteins unchanged differ in their action upon the various classes of these compounds. 

Salting out or precipitation by varying the salt type and concentration is often used in the early stages of purification of proteins from complex mixtures. 

Reid, G.E. Shang, H. Hogan, J.M. Lee, G.U. McLuckey, S.A. Gas-phase concentration, purification, and identification of whole proteins from complex mixtures. J. Am. Chem. 

Electrophoresis is a method with superior resolution used to separate macromolecules from complex mixtures by the application of an electric field. The macromolecules, placed at one end of the matrix and called the gel, are subjected to an electric field. Different macromolecules in the gel will migrate at different speeds, depending on the nature of the gel and the characteristics of the macromolecules. Electrophoretic techniques can be used to separate any biomacromolecule such as nucleic acids, polypetides, and carbohydrates. Tiselius [25] won the Nobel Prize in chemistry in 1948 for his work on the development of electrophoresis as a technique to separate and characterize proteins from complex mixtures. 

---