The Effect of (H+) 0n alfa-amilase activity isolated from bacillus subtilis

The effect of [KT] ions on a-amylase activity which was isolated from Bacillus subtilis was investigated. We first tried to determine the appropriate enzyme concentration and incubation time. Results obtained showed that appropriate enzyme concentration is 3.10"3 jig/uL and appropriate incubation time is 15 minutes. Optimal pH value was determined in appropriate enzyme concentration, different pH values and substrate concentrations both with pre-incubation for 120 minutes and without pre-incubation. Optimal pH was found to be 7.12 in both conditions. To examine the effect of pH on enzyme stability, the enzyme was pre- incubated for 120 minutes in constant substrate concentration ([S]: 2.52 ug/uL) and in previously obtanied pH value. pHi=pHa, pH2=pHb And optimal pH values were found to be 6.15, 8.68 and 7.415_respectively. Km and Vmax values for the enzyme were found by using Michaelis-Menten kinetics in different pH values KM 4.898; 4.7311; 5.004; 1.4615; 0.2483; 1.6666 and Vmax 2.023; 2.431; 2.542; 0.952; 0.117; 0.438 Tippon, Dixon and Webb theories can not be applied to a system contains an oligomeric enzyme and a substrate in a macromolecular structure.