title: Electrochemical extraction of proteins by reverse micelle formation.
abstract: The transfer of proteins by the anionic surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) at a polarized 1,2-dichloroethane/water (DCE/W) interface was investigated by means of ion-transfer voltammetry. When the tetrapentylammonium salt of AOT was added to the DCE phase, the facilitated transfer of certain proteins, including cytochrome c (Cyt c), ribonuclease A, and protamine, could be controlled electrochemically, and a well-defined anodic wave for the transfer was obtained. At low pH values (e.g., pH 3.4), the anodic wave was usually well-separated from the wave for the formation of protein-free (i.e., unfilled) reverse micelles. The anodic wave for the protein transfer was analyzed by applying the theory for facilitated transfer of ions by charged ligands and then supplying information regarding the number of AOT anions reacting with one protein molecule and the total charge carried by the protein transfer. However, controlled-potential electrolyses performed for the transfer of Cyt c, which is red, revealed that the protein-AOT complexes were unstable in DCE and liable to aggregate at the interface when the pH of the W phase was 3.4. At pH 7.0, when formation of unfilled reverse micelles occurred simultaneously, the protein-AOT complexes appeared to be stabilized, probably via fusion with unfilled reverse micelles.
authors.affiliation: Department of Chemistry, Faculty of Science, Kobe University, Nada, Kobe 657-8501, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Shinshi
authors.forename: Takayasu
authors.initials: T
authors.lastname: Sugihara
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Osakai
authors.forename: Masahiro
authors.initials: M
authors.lastname: Goto
mesh_terms: D000818:Animals; D045304:Cytochromes c / Q000302:isolation & purification; D004563:Electrochemistry; D004572:Electrolysis; D005025:Ethylene Dichlorides; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D011479:Protamines / Q000302:isolation & purification; D011506:Proteins / Q000302:isolation & purification*; D012259:Ribonuclease, Pancreatic / Q000302:isolation & purification; D013386:Succinates; D013501:Surface-Active Agents; D014867:Water
chemical_list: C512554:1,4-bis(2-ethylhexyl) sodium sulfosuccinate; D005025:Ethylene Dichlorides; D008823:Micelles; D011479:Protamines; D011506:Proteins; D013386:Succinates; D013501:Surface-Active Agents; D014867:Water; C024565:ethylene dichloride; D045304:Cytochromes c; D012259:Ribonuclease, Pancreatic