title: An efficient enzymatic modification of cordycepin in ionic liquids under ultrasonic irradiation.
abstract: A comparative study of the immobilized Candida antarctica lipase B (Novozym 435)-catalyzed acylation of cordycepin with vinyl acetate in ionic liquids (ILs) under ultrasonic irradiation and shaking was conducted. The application of ultrasonic irradiation instead of shaking during acylation resulted in an enhanced reaction rate and a higher level of substrate conversion. Among the various ILs examined, 1-butyl-3-methylimidazolium tetrafluorobrate ([C4MIm][BF4]) was the best medium for the reaction because it produced the highest substrate conversion. In [C4MIm][BF4], the optimal ultrasonic power, water activity, and reaction temperature were 120 W, 0.33, and 50 °C, respectively. The acylation of cordycepin in [C4MIm][BF4] proved to be regioselective under both conditions: the C5'-OH was acylated. Novozym 435 exhibited a much higher operational stability in [C4MIm][BF4], and 58.0% of its original activity was maintained after ten reuse cycles under ultrasonic irradiation. Compared with the cordycepin, the rate of adenosine deaminase-catalyzed deamination was greatly reduced when the 5'-OH was substituted by acetyl group. These results demonstrated that the combined application of ultrasonic irradiation and IL as a medium was an efficient approach for the enzymatic modification of cordycepin.
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Dan-Ni
authors.initials: DN
authors.lastname: Zhang
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Guo
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Qiu-Huizi
authors.initials: QH
authors.lastname: Yang
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: zgchen@njau.edu.cn.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Chen
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Tao
mesh_terms: D000107:Acetylation / Q000528:radiation effects; D003839:Deoxyadenosines / Q000737:chemistry* / Q000528:radiation effects*; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D007477:Ions / Q000737:chemistry / Q000528:radiation effects; D008049:Lipase / Q000737:chemistry* / Q000528:radiation effects*; D013696:Temperature; D014465:Ultrasonics / Q000379:methods*; D014753:Vinyl Compounds / Q000737:chemistry / Q000528:radiation effects
chemical_list: D003839:Deoxyadenosines; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D007477:Ions; D014753:Vinyl Compounds; C093667:Novozyme 435; D008049:Lipase; C058120:cordycepin; C011566:vinyl acetate
keywords: Cordycepin; Enzymatic acylation; Ionic liquids; Regioselectivity; Ultrasonic irradiation