Thermal Stability of Cathepsin D

The effect of pH and temperature on Cathepsin D stability was examined using a hemoglobin assay following preincubation of the enzyme at various pH and temperature combinations. The results of the study showed that the enzyme retained 87% of its activity at 45°C (pH 3.5) when compared to a control at 37°C (pH 3.5). Further increases in temperature and pH resulted in decreased enzyme activity and approximately 43% remained at 55°C (pH 5.5). The amount of activity remaining at higher temperatures decreased but suggests that the enzyme could contribute to textural changes in meat at temperatures up to 60°C.