Figure 6.

Effect of temperature on the thermal stability of miswak α-amylases A1, A4a, A4b, A5a and A5b. The reaction mixture contained in 0.5 ml: 50 mM Tris-HCl buffer, pH 7.5 and suitable amount of enzyme. The reaction mixture was preincubated at various temperatures for 30 min prior to substrate addition, followed by cooling in an ice bath. The enzyme activity was measured using the standard assay method as previously described. Activity at zero time was taken as 100% activity. Each point represents the average of two experiments.