Phosphate buffer effects on thermal stability and H_2O_2-resistance of horseradish peroxidase

摘要

Horseradish peroxidase (HRP) has attracted intense research interest due to its potential applications in biotechnological fields. However, inadequate stability under prevalent conditions such as elevated temperatures and H_2O_2 exposure, has limited its industrial application. In this study, stability of HRP was investigated in the presence of different buffer systems (potassium phosphate and Tris–HCl) and additives. It was shown that the concentration of phosphate buffer severely affects enzyme thermostability in a way that in diluted potassium phosphate buffer (10mM) half-life (from 13 to 35 min at 80 ?C) and Tm (from 73 to 77.5 ?C) increased significantly. Among additives tested, trehalose had the most thermostabilizing effect. Exploring the role of glycosylation in stabilizing effect of phosphate buffer, non-glycosylated recombinant HRP was also examined for its thermal and H_2O_2 stability in both diluted and concentrated phosphate buffers. The recombinant enzyme was more thermally stable in diluted buffer in accordance to glycosylated HRP; but interestingly recombinant HRP showed higher H_2O_2 tolerance in concentrated buffer.