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Factors Affecting Protein Transfer into Surfactant−Isooctane Solution: A Case Study of Extraction Behavior of Chemically Modified Cytochrome c
Author(s) -
Ono Tsutomu,
Goto Masahiro
Publication year - 1998
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp9800844
Subject(s) - chemistry , pulmonary surfactant , cytochrome c , extraction (chemistry) , aqueous two phase system , moiety , phosphoric acid , lysine , aqueous solution , chromatography , hydrogen bond , organic chemistry , molecule , amino acid , biochemistry , mitochondrion
The extraction mechanism of proteins by surfactant molecules in an organic solvent has been investigated using a chemically modified protein. We conducted guanidylation on lysine residues of cytochrome c by replacing their amino groups with homoarginine to enhance the protein−surfactant interaction. Results have shown that guanidylated cytochrome c readily forms a hydrophobic complex with dioleyl phosphoric acid (DOLPA) through hydrogen bonding between the phosphate moiety and the guanidinium groups. Although improved protein−surfactant interaction activated the formation of a hydrophobic complex at the interface, it could not improve the protein transfer in isooctane. It has been established that the protein extraction mechanism using surfactant molecules is mainly governed by two processes: formation of an interfacial complex at the oil−water interface and the subsequent solubilization of the complex into the organic phase. In addition, a kinetic study demonstrated that guanidylation of lysine accelerated the initial extraction rate of cytochrome c . This fact implies that the protein transferability from aqueous phase into organic phase depends on the protein−surfactant interaction which can be modified by protein surface engineering.