Bioconjugation of lipase and cholesterol oxidase with graphene or graphene oxide

摘要: The catalytic behavior of lipase and cholesterol oxidase (ChOx) in the absence presence graphene (G) or oxide (GO) was investigated at 24 ± 1 °C pH 6.5. GO flat sheets (0.5–2 μm) were ~2-nm thick, while G formed aggregates. maximum reaction velocity (V max) values turnover numbers (k cat) determined for reactions catalyzed by physical mixtures (at 0.01 g l−1) ChOx 0.03 g l−1) (0.012 g l−1) increased six-fold doubled, respectively, comparison to neat enzymes. Circular dichroism (CD) photoluminescence (PL) spectroscopic measurements revealed preservation native secondary structures enzymes bioconjugation driven hydrophobic interaction energy transfer (redshift) between G, corroborating with enhanced behavior. On other hand, interactions GO, which has hydrophilic moieties on basal plane, caused enzyme deactivation, as evidenced typical CD signal. At low concentration (<0.012 g l−1), bioconjugates lipases led V max k cat four-fold lower than their counterparts but groups probably favored affinity substrate, because Michaelis constant (Km) decreased that lipase. Upon increasing concentration, lost structure PL bands disappeared.