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Catalytic and Structural Properties of Surfactant‐Horseradish Peroxidase Complex in Organic Media
Author(s) -
Kamiya Noriho,
Inoue Masahito,
Goto Masahiro,
Nakamura Nobuhumi,
Naruta Yoshinori
Publication year - 2000
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/bp990125b
Subject(s) - chemistry , horseradish peroxidase , pulmonary surfactant , catalysis , aqueous solution , aqueous two phase system , cationic polymerization , inorganic chemistry , organic chemistry , enzyme , biochemistry
A surfactant‐horseradish peroxidase (HRP) complex that is catalytically active in organic media has been successfully prepared by a method utilizing water‐in‐oil (W/O) emulsions. To optimize conditions for preparation of the HRP complex, the effects of some key parameters in the aqueous phase of W/O emulsions were investigated. The surfactant‐HRP complex prepared with a nonionic surfactant exhibited a high catalytic activity compared to those with a cationic or anionic surfactant in anhydrous benzene. At the preparation step, the pH of the aqueous solution had a prominent effect on the enzymatic activity of the HRP complex in organic media. Several kinds of salts present in the HRP complex could be employed to enhance the catalytic performance in organic media. However, anionic ions present in the preparation process appeared to lower the catalytic activity owing to the complexation with heme iron. UV‐visible absorption spectra of the HRP complex in benzene, which were prepared from a KCN solution (pH 7.0) or an alkaline solution (pH 12), were comparable with those of native HRP in aqueous solution under the same conditions. Resonance Raman spectroscopic studies also revealed that no significant change in the coordination state of the heme iron occurred even after coating the enzyme with surfactant molecules, lyophilization, and solubilization in nonaqueous media.