A solution was made up with p-Nitrophenyl phosphate (pNPP), 0.1 M borate buffer at pH 9.5 and and alkaline phosphatase. This solution has good enzyme activity (Figure 1). A solution was made up with p-Nitrophenyl phosphate (pNPP), 0.1 M borate buffer at pH 7.0 and and alkaline phosphatase. Why does changing the pH to 7 decrease the apparent activity of alkaline phosphatase (Figure 2).

PLEASE GO IN DEPTH, talk about reasons centred on enzyme structure and function.

FIgure 1

Figure 2

Table 1: Absorbance (405 nm) change per time at different substrate concentrations Time (s) 0 15 30 45 60 75 90 105 120 135 150 165 180 0.075 mm* 0 0.005 0.008 0.011 0.015 0.018 0.022 0.026 0.029 0.033 0.036 0.04 0.043 Absorbance (405 nm) 0.3 mm* 0.75 mm* 1.2 mm* 0 O 0 0.017 0.022 0.026 0.03 0.043 0.073 0.055 0.07 0.113 0.075 0.092 0.153 0.098 0.12 0.186 0.117 0.145 0.235 0.133 0.17 0.277 0.152 0.2 0.318 0.176 0.24 0.36 0.192 0.262 0.402 0.211 0.31 0.445 0.231 0.356 0.488 1.5 mm* 0 0.043 0.095 0.136 0.179 0.222 0.265 0.31 0.351 0.394 0.437 0.48 0.523 Time (s) 0 15 30 45 60 75 90 105 120 135 150 165 180 0.075 mm* 0 o 0.002 0.002 0.002 0.003 0.003 0.003 0.004 0.004 0.004 0.005 0.005 Absorbance (405 nm) 0.3 mm* 0.75 mm* 1.2 mm* 0 0 0 0.001 0.002 0.003 0.002 0.003 0.004 0.003 0.003 0.005 0.004 0.004 0.006 0.004 0.005 0.008 0.004 0.006 0.01 0.005 0.007 0.012 0.005 0.008 0.014 0.006 0.008 0.017 0.006 0.009 0.018 0.007 0.01 0.02 0.008 0.011 0.022 1.5 mm* 0 0.005 0.008 0.01 0.015 0.019 0.024 0.031 0.035 0.04 0.046 0.051 0.057 Table 1: Absorbance (405 nm) change per time at different substrate concentrations Time (s) 0 15 30 45 60 75 90 105 120 135 150 165 180 0.075 mm* 0 0.005 0.008 0.011 0.015 0.018 0.022 0.026 0.029 0.033 0.036 0.04 0.043 Absorbance (405 nm) 0.3 mm* 0.75 mm* 1.2 mm* 0 O 0 0.017 0.022 0.026 0.03 0.043 0.073 0.055 0.07 0.113 0.075 0.092 0.153 0.098 0.12 0.186 0.117 0.145 0.235 0.133 0.17 0.277 0.152 0.2 0.318 0.176 0.24 0.36 0.192 0.262 0.402 0.211 0.31 0.445 0.231 0.356 0.488 1.5 mm* 0 0.043 0.095 0.136 0.179 0.222 0.265 0.31 0.351 0.394 0.437 0.48 0.523 Time (s) 0 15 30 45 60 75 90 105 120 135 150 165 180 0.075 mm* 0 o 0.002 0.002 0.002 0.003 0.003 0.003 0.004 0.004 0.004 0.005 0.005 Absorbance (405 nm) 0.3 mm* 0.75 mm* 1.2 mm* 0 0 0 0.001 0.002 0.003 0.002 0.003 0.004 0.003 0.003 0.005 0.004 0.004 0.006 0.004 0.005 0.008 0.004 0.006 0.01 0.005 0.007 0.012 0.005 0.008 0.014 0.006 0.008 0.017 0.006 0.009 0.018 0.007 0.01 0.02 0.008 0.011 0.022 1.5 mm* 0 0.005 0.008 0.01 0.015 0.019 0.024 0.031 0.035 0.04 0.046 0.051 0.057