Furukawa Makoto, Kawakami Norifumi, Oda Kohei, Miyamoto Kenji
Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.
Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
ChemSusChem. 2018 Dec 11;11(23):4018-4025. doi: 10.1002/cssc.201802096. Epub 2018 Nov 27.
Enzymatic degradation of poly(ethylene terephthalate) (PET) is promising because this process is safer than conventional industrial approaches. Recently, a cationic PET hydrolase (PETase) was identified from Ideonella sakaiensis. Pre-incubation of a low-crystallinity PET film with anionic surfactants prior to initiating the reaction was found to improve PETase activity 120-fold. After 36 h at 30 °C, the film thickness decreased by 22 %. The binding of surfactants to the film makes the surface anionic, thereby attracting the cationic PETase. Mutagenesis of PETase showed that the surface cationic region formed by R53, R90, and K95, which are located on the same side as the substrate binding pocket, was crucial for efficient acceleration of activity by the anionic surfactant. Thus, surfactant bound on PET aligns the orientation of the active site to the surface, resulting in efficient hydrolysis. We believe that this approach using PETase could be further improved by designing surfactant molecules for the more efficient enzymatic PET degradation.
聚对苯二甲酸乙二酯（PET）的酶促降解很有前景，因为这个过程比传统工业方法更安全。最近，从食酸戴尔福特菌中鉴定出一种阳离子PET水解酶（PETase）。发现在开始反应前用阴离子表面活性剂对低结晶度PET薄膜进行预孵育可使PETase活性提高120倍。在30℃下反应36小时后，薄膜厚度减少了22%。表面活性剂与薄膜的结合使表面带负电，从而吸引阳离子PETase。PETase的诱变表明，由位于与底物结合口袋同一侧的R53、R90和K95形成的表面阳离子区域对于阴离子表面活性剂有效加速活性至关重要。因此，结合在PET上的表面活性剂使活性位点与表面的方向对齐，从而实现高效水解。我们相信，通过设计用于更高效酶促PET降解的表面活性剂分子，这种使用PETase的方法可以得到进一步改进。
