Boron increases the transition temperature and enhances thermal stability of heme proteins

Abstract Transition temperature and thermal stability of proteins were studied in the presence and absence of boron. The observed midpoint of thermal denaturation (Tm) of cytochrome c (Cyt c) at pH 9.2 was 68.8 °C, which in the presence of boron increased to 71.0 °C. For metmyoglobin, Tm increased from 79.7 °C in the absence of boron to 83.5 °C in the presence of boron. Boron caused an increase of 10% in the reversibility of thermal denaturation of cytochrome c when compared with control. Activity measurements of the heat treated proteins and Tm suggest an increased thermal stability toward inactivation and denaturation of heme proteins in the presence of boron.