Abstract:A gene (sbnag2550) encoding N-acetyl-glucosaminidase (NAGase) was cloned from Streptomyces bacillaris and expressed in Escherichia coli BL21(DE3). The enzymatic properties of SbNag2550 were studied using the purified enzyme obtained by nickel ion affinity chromatography. The optimal temperature of SbNag2550 was 50 ℃, and it could show more than 90% activity at temperature ranging from 45 ℃ to 60 ℃. The enzyme also showed excellent thermostability, retaining nearly 90% activity after incubating at 55 ℃ for 60 h. SbNag2550 was used to catalyze the reverse hydrolysis reaction of N-acetyl-glucosamine (NAG) and glycerol, realizing the synthesis of glyceryl N-acetyl-glucosamine (GNAG). Under optimal conditions, the conversion rate reached 28.20% and 34.82% at 24 h and 72 h, respectively. GNAG was firstly synthesized by enzymatic catalysis in this study, which laid a foundation for its functional research and application development.
