Improvement of chondroitinases ABCI stability in natural deep eutectic solvents

Abstract

Deep eutectic solvents (DESs) are of great importance in enzymatic reactions. They facilitate the effective contact between reactants and enzymes, thereby can affect the activity, structure and stability of enzymes. Chondroitinase ABCI (cABCI) is an important clinical enzyme in the treatment of spinal lesions. The low stability of this enzyme, however, limits its commercial application. Therefore, in the current study, activity, stability and tertiary structure of cABCI enzyme from Proteus vulgaris was investigated in betaine and choline based DESs with glycerol as a hydrogen bond donor. Deep eutectic solvents (2 glycerol:1 choline chloride (Gly2C) and 2 glycerol:1 betaine (Gly2B)) exhibited a better media for enhancing cABCI stability at −20, 4 and 37°C when compared to the buffer. At 37°C, the enzyme in Gly2C and Gly2B retained about 82% of its initial activity after 120min, while the enzyme activity reached 20% in the absence of DESs. At −20°C, the enzyme retained 95% and 80% of its initial activity in Gly2C and Gly2B after 15days, respectively, but in the absence of DES lost its total activity after 5days. Beside the enzyme activity, conformational changes caused by both DESs were monitored using fluorescence technique. The enzyme in Gly2C revealed more compact structure than the enzyme in Gly2B due to higher fluorescence intensity.