Protein extraction and activity in reverse micelles of a nonionic detergent

Abstract

We describe, for the first time, the ability of a polyoxyethylene sorbitan trioleate-isopropanol microemulsion in hexane to solubilize pure proteins. The dependences of cytochrome c extraction and buffer solubilization by the reverse micellar system on ionic strength of the aqueous phase, detergent concentration, and cosurfactant concentration result in increased extraction. In addition, subtilisin (a serine protease) is shown to be active in this microemulsion. Further the activity of the enzyme can be regulated by the water content of the micelles, enabling control of enzyme activity by "solvent engineering."

Role of the Interface in Protein Extractions Using Nonionic Microemulsions

“…has been used previously in the literature to extract proteins (8). Several models have been proposed to characterize protein extraction into reverse micelles, in the absence of affinity ligands (6,15).…”

“…Nonionic surfactant microemulsions for minimum, all of the protein is removed. It was also observed that protein extraction have been studied more recently and are below this minimum the protein-specific surfactant is present at not as well characterized (4,8). In general, ionic microemulthe oil-water interface, but is not available for protein extraction.…”

His‐tagged protein purification by metal‐chelate affinity extraction with nickel‐chelate reverse micelles

“…Reverse micelles of nonionic surfactants have very low protein solubilization capacity due to the weak interactions between the reverse micelles and proteins. [8][9][10] By introducing an affinity ligand into such a mild system, selective protein extraction based on affinity interactions can be realized under a mild condition, as demonstrated by a lot of publications. [11][12][13][14][15][16][17][18] To date, trypsin inhibitor, 12,14 antibody, 16 Cibacron Blue F-3GA, 13,15,17,18 and chelated copper(II) ions 11 have been used for affinity-based reverse micellar extractions.…”

A metal‐chelate affinity reverse micellar system for protein extraction

“…[13][14][15][16][17][18] To solve the second problem, researchers have attempted to use nonionic surfactants to form reverse micelles to weaken the electrostatic interactions between the reverse micelles and proteins. [19][20][21] In the case of affinitybased protein extraction with ionic reverse micelles, there were still strong electrostatic interactions beyond the affinity effect under usual extractive conditions, so the affinity effect was more significant at the range of very high ionic strength 15 or pH where electrostatic interactions were weakly attractive or even repulsive. 13,14 Hence, it is desired to incorporate an affinity ligand into nonionic surfactant reverse micelles to simultaneously increase extraction selectivity and offer a mild condition for protein accommodation.…”