Regular articleSwitch on/off of cellulase activity based on synergetic polymer pair system

- The cellulase activity can be regulated by copolymer at room temperature.
- The thermal stability of cellulase was increased obviously by copolymer.
- The secondary structure of cellulase was not destroyed throughout the process.

Cellulase has enormous potential applications in various industries, including food, textiles, and paper, etc. However, undesirable heat-induced misfolding is considered as one of the major problem in cellulase application. So, we have designed a practical and efficient synergetic polymer pair system (SPPS), which can regulate and preserve the enzymatic activity of cellulase with a pair of oppositely charged polymers. First, we designed and synthesized a copolymer, poly(ethylene- glycol)-graft-poly(N,N-dimethylaminoethyl methacrylate) (PEG-g-PDMAEMA) with hydrophilic and cationic chains, which was connected with anionic cellulase to form a water-soluble cellulase/PEG-g-PDMAEMA complex to inhibit the enzymatic activity of cellulase completely without loss of secondary structure. In the second step, the enzymatic activity of enzyme/copolymer complex was recovered successfully with the addition of an anionic polymer, poly(acrylic acid) (PAAc). What surprised us was that 81% of the enzymatic activity of the cellulase/PEG-g-PDMAEMA complex was restored after 10 min of heating at 90 °C. Circular dichroism (CD) spectral analysis clearly indicated that there was no significant impact on the conformation of the cellulase of heat-treated enzyme/copolymer complex.

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