In this experiment, the effect of substrate concentration on the activity of the purified alginate lyase enzyme was examined. The sodium alginate concentration used in the reaction mixture was varied in a range of 1 to 10 mg/ml reaction mixture. The reaction was carried at 37°C for 20 minutes.
The results given in Table 26 and illustrated in Fig. 26 indicated that the optimum substrate concentration for the pure enzyme was 8 mg/ml reaction mixture. At this concentration, the highest specific activity was recorded. Further increase of substrate concentration yielded a slightly lower enzyme activity. According to these results, a substrate concentration of was 8 mg/ml reaction mixture was used in the next experiment. The results in Fig. 27 showed that Km and Vmax values of the purified enzyme were found to be 1.06 mg alginate/ml and 217.4 U/mg protein respectively.…show more content… Effect of pH of the reaction
The effect of pH of the reaction on the activity of the purified alginate lyase enzyme was studied. A pH range of 3.5 to 8 was used (acetate buffer, 0.05M; phosphate buffer, 0.05M). The enzymatic reaction was carried out for 20 minutes at 37°C using a substrate concentration of 8 mg/ml reaction mixture.
The results in Table 27 and Fig. 28 indicated that the purified enzyme showed maximum specific activity at pH 7.5. Higher or lower pH values showed an adverse effect on the activity and the lowest activity was obtained at pH 3.5 showing about 48.5% decrease of the value obtained at pH 7.5. However, the enzyme showed to be a relatively stable in a pH range from 5.5 to 7.5.
3.9.3. Effect of temperature of the reaction
The influence of the reaction temperature on the activity of the purified enzyme was investigated. Different temperatures 30, 37, 40, 45, 50 and 60 °C were tested. The enzymatic reaction was carried out for 20 minutes at pH 7.5 using a substrate concentration of 8 mg/ml reaction