abstract
L-Asparaginase (ASNase) is a high value enzyme for the pharmaceutical and food industries. Although ionic liquids (ILs) have been recognized as promising solvents or additives for biocatalysis, there are very few studies on the effect of ILs on the activation of ASNase. To address this, the enzymatic activity of a commercial ASNase in aqueous ILs was evaluated. ASNase was exposed for up to 24 h to aqueous solutions (0.001-0.050 mol.mol(-1)) of cholinium ([Ch])-based ILs, at three temperatures (25, 37, and 50 degrees C). At 25 degrees C, [Ch]-based IL aqueous solutions enhanced the biocatalytic activity of ASNase, with a maximum increase of the relative ASNase activity (of ca. 250%) achieved by adding cholinium chloride ([Ch]Cl). Spectroscopic and calorimetric analyses were performed to understand the effect of [Ch]Cl on the ASNase structure, but no significant changes were observed. Although all [Ch]-based ILs enhanced the relative ASNase activity, the positive effects were diminished with increasing the anion alkyl chain length, i.e. from acetate to hexanoate. The increase of temperature to 50 degrees C caused a negative effect in the catalytic behavior of ASNase, leading, in most cases, to ASNase inactivation. Overall it was evident that [Ch]-based ILs are highly efficient biocatalytic additives to enhance ASNase activity in water (a 2-fold increase by adding less than 0.050 mol.mol(-1)). This simple and useful approach can be applied to increase the sustainability of several ASNase biocatalytic applications, especially in food processes.
keywords
ACUTE LYMPHOBLASTIC-LEUKEMIA; TRYPTOPHAN FLUORESCENCE; HOFMEISTER SERIES; CYTOCHROME-C; STABILITY; PROTEINS; GREEN; IMPROVEMENT; HEMOGLOBIN; HYDROLYSIS
subject category
Chemistry; Science & Technology - Other Topics; Engineering
authors
Magri, A; Pecorari, T; Pereira, MM; Cilli, EM; Greaves, TL; Pereira, JFB
our authors
Jorge Fernando Brandão Pereira
PhD Student
Matheus M. Pereira
Researcheracknowledgements
This work was developed in the scope of the projects FAPESP 2014/16424-7 and 2018/50009-8 and supported by the funding of Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior CAPES/PROEX (001). A.M. and M.M.P. acknowledge the Ph.D. grant (163292/2015-9 and 2740-13-3, respectively) and financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico CNPq.