Spectroscopic and mechanistic analysis of the interaction between Jack bean urease and polypseudorotaxane fabricated with bis-thiolated poly(ethylene glycol) and α-cyclodextrin.

Self-assembled polypseudorotaxanes (PPRXs) fabricated with α-cyclodextrin and poly(ethylene glycol) (PEG) or its thiolated derivatives were candidate functional materials for enzyme soft-immobilization, encapsulation and controlled-release. The study of their interaction with Jack bean urease (JBU) indicated that they inconspicuously influenced the activity and stability of JBU during long storage, up to 30 days. The macro-species were inaccessible to JBU's active site and the steric effect might play a significant role in the stabilization of JBU, when compared with the small-molecular sulfhydryl inhibitor thioglycolic acid.

α-chymotrypsin activated and stabilized by self-assembled polypseudorotaxane fabricated with bis-thiolated poly(ethylene glycol) and α-cyclodextrin: Spectroscopic and mechanistic analysis.

The self-assembled polypseudorotaxane (PPRX) fabricated with bis-thiolated poly(ethylene glycol) (PEG) and α-cyclodextrin (α-CyD) acted as an activator for α-chymotrypsin (CT) and retained the activity of CT for a long time up to 7days. The stabilization mechanism was studied, and the interaction between CT and PPRX was analyzed by using circular dichroism, fluorescence spectra and X-ray powder diffraction (XRD). The bis-thiolated PEG and its assembled PPRX with α-CyD exhibited the interaction with the C-terminal region of the CT's B-chain probably through PEGylation of the surface disulfide bridge of CT.