Site-specific immobilization of cytochrome c on mesoporous silica through metal affinity adsorption to enhance activity and stability

Shih Hsun Cheng, Kun Che Kao, Wei Neng Liao, Li Ming Chen, Chung Yuan Mou, Chia Hung Lee

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

We report a hydrothermally stable and highly reactive cytochrome c (cyt c) immobilized in the nanochannels of mesoporous silica (SBA-15) through a metal affinity interaction. Due to the strong affinity of mercury-sulfuric bonds, we modified the SBA-15 surfaces with 4-aminophenylmercuric acetate (APMA) groups. As a result, an enzyme molecule (yeast cyt c) with a cysteine residue (cys-102) demonstrated strong adsorption, which provided high cyt c loading amounts, highly catalytic activity, and high stability against hydrothermal processes and organic solvents. To compare the immobilization of cysteine-containing cyt c through metal affinity interactions and a traditional covalent bond (a disulfide bond), we modified the SBA-15 surfaces with 3-mercaptopropyl-trimethoxysilane (MPTS) for further production of a disulfide bond with the cysteine residue of cyt c. The cysteine residue of the cyt c can covalently link to thiol-modified SBA-15 through the formation of a disulfide bond. In addition, a non-specific coordination from the thiol groups of SBA-15 to the heme Fe(iii) of cyt c may destroy the catalytic center and cause the leaching of Fe(iii) ions. Our previous studies of the molecular model have shown that the immobilization of cyt c through the cysteine residue can provide a correct orientation of the catalytic center, where the active site can easily approach the substrate molecules. Therefore, we have developed rapid and highly efficient approaches to immobilize a cysteine-containing enzyme through APMA ligands, which can both protect the protein folding and control the orientation to optimize the stability and catalytic activity.

Original languageEnglish
Pages (from-to)1809-1816
Number of pages8
JournalNew Journal of Chemistry
Volume35
Issue number9
DOIs
Publication statusPublished - Sep 2011
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Materials Chemistry

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