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Carbon nanotube has been proved as a kind of novel support for enzyme immobilization.In this study,we performed a series of experiments to find the relationship between protein conformation and catalytic performance,using different carbon nanotubes (SWCNT and MWCNT),immobilize methods (physical adsorption and covalent binding) and C-C bond hydrolases (BphD and MfphA).The results showed that catalytic performance of immobilized enzyme depends on specific enzyme,immobilization method and type of carbon nanotube.Immobilized BphD based on chemical modified SWCNT (BphD-CSWCNT) has the highest activity and exhibited a comparable catalytic efficiency with free BphD (92.g%).However,when MfphA bound to pristine SWCNT (MfphA-SWCNT),it lost activity completely.Time-resolved fluorescence spectrum indicated static ground complexes formed during all of the immobilization processes.Circular dichroism (CD) of immobilized enzymes showed that the secondary structures changed in varying degrees.In order to investigate the inhibition mechanism of SWCNT on MfphA,we used molecular dynamics simulation of SWCNT-MfphA conjugate to analyze the adsorption process,binding sites and time evolution of substrate tunnels.The results indicated that the preference binding sites (Trp201 and Met81) blocked the main tunnel of MfphA,which can be a novel possible inhibition mechanism for enzyme-nanotube conjugate.