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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