Affinity precipitation of proteins: design criteria for an efficient polymer

Abstract

Affinity precipitation is fast emerging as a successful technique for the purification of proteins which can be introduced at an early stage of downstream processing. The technique applies the use of reversibly soluble-insoluble polymers which have either natural or synthetic origin. Apart from the successful use of some natural polymers, such as chitosan and alginate, the vast application of the technique depends upon the design of efficient synthetic polymers. In this laboratory, N-isopropylacrylamide (NIPAM) copolymers have been developed for metal chelate affinity precipitation of proteins. The copolymers of 1-vinylimidazole (VI) and iminodiacetic acid (IDA) with NIPAM were synthesized. The copolymers were thoroughly characterized with a view to designing an efficient soluble-insoluble polymer for metal chelate affinity precipitation of proteins.

“Protein-Like” Copolymers: Effect of Polymer Architecture on the Performance in Bioseparation Process

“…Once, the protein is dissociated from the macroligand, the ligand-polymer conjugate is precipitated again without the protein, which remains in the supernatant in a purified form. [17] STI is a small protein of molecular weight of 22 000 Da having inherent histidine residues at the surface of the globule and hence high affinity towards immobilized metal ions. It was nearly quantitatively coprecipitated with poly(NIPAAM-VI) copolymers in the presence of Cu 2+ -ions with increasing salt concentration.…”

Polyethyleneimine phosphate and citrate systems act like pseudo polyampholytes as a starting method to isolate pepsin

“…The protein precipitate is produced through a two-stage process: the formation of protein-polyelectrolyte complexes and the complex aggregation between them to form an insoluble state [8].…”

Thermoresponsive Properties of Sugar Sensitive Copolymer of N‐Isopropylacrylamide and 3‐(Acrylamido)phenylboronic Acid

“…[1][2][3][4][5] Stimuli-responsive polymers are studied for the development of biomimetic actuators, immobilized biocatalysts, drug delivery systems, thermoresponsive surfaces, and for bioseparation. [1,3,[6][7][8][9][10][11][12][13][14][15][16] The structure and behavior of stimuli-responsive polymers in aqueous solution is also quite interesting in connection with biopolymers playing an important role in life, such as proteins, enzymes, nucleic acids, and polysaccharides. [2,3] One intensively studied stimuli-responsive polymers is poly-N-isopropylacrylamide and its derivatives.…”

“…[4] Affinity precipitation [1,6,8,11 -15] and affinity aqueous two-phase partitioning [6] are quite powerful methods for the affinity separation of proteins. These methods are based on complex formation of the affinity ligand of the polymer with the target protein, phase transition of the polymer triggered by stimuli, and finally desorption of the purified protein from the polymer.…”