Structure and Catalytic Behavior of Immobilized Enzymes

The immobilization of enzymes onto CNTs leads in most cases in the stabilization of the immobilized enzyme [108, 135], The stability was further enhanced when covalent bond between the enzyme and the nanomaterials were used [13, 119, 137]. The covalent bond prevents the enzyme leakage during repeating used of the enzyme-nanomaterial conjugates. When the enzymes are non-covalently attached onto the nanomaterials, the enzyme molecules are in equilibrium between the solid state (the microenvironment of the nanomaterial) and the bulk liquid phase, so that in every use some molecules are detached from the nanomaterial. 

Protein Nanomaterials Spectroscopic Techniques Results Reference 

Myoglobin Bmim[BF4]- SWCNTs CD UV-Vis No structural changes observed upon immobilization [108] 

Albumin ovalbumin carbonic anhydrase hemoglobin hexokinase MWCNTs MWCNT-COOH MWCNT-tyrosine MWCNT-isobutane amine CD Fluorescence The functionalized MWCNTs selectively induced protein secondary structure changes. Structural changes depend on the enzyme used and the functional group and the concentration of MWCNTs. [136] 

Albumin lysozyme SWCNTs CD Vis-Near IR The proteins are partially unfolded upon immobilization. [128] 

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