Question

0:14 0.121 0.1 9.08 osoby 0.04+ 0.02 OH -0.olt the seconds) -0.03 + INTERPRÉTATION Althonoi Methanol isopropound Did you observe any difference in the final measured absorbante (.e., the absorbance at 60 seconds) for the different substrates used? Explain how the absorbances vary between substrates. The absorbance was very low for Methanol, it was higher for Isopropanol & excen higher for acetone, & all absorbances for those 3 substrates were less than that of ethanol Consider the enzyme activity with changing substrate. Which substrate produced NADH most quickly? What does this imply about how well each substrate binds? Acetone

Answer 1

Enzyme -Substrate activity exp. :

• There is drastic increase in abosrbance in case of Ethanol, but very less increase in Absorbance in case of methanol and isoproanol. But change in absorbance in case of Acetone.
• This experiment clearly indicates change in enzyme activity with changing substrate : Absorbance is due to NADH ( NADH produced during experiment is observed directly by absorbnace ).

     Ethanol + NAD+    ==(ADH) ===> Acetaldehyde + NADH   ( Ethanol produced NADH most quickly, High substrate specificity -: ethanol binds with enzyme with high affinity )

   Methanol + NAD+    ==(ADH) ===> Formaldehyde + NADH ( Slow reaction , thus very slow production of NADH : poor substrate binding )

    Isopropanol + NAD+    ==(ADH) ===> Acetone + NADH    ( Slow reaction , thus very slow production of NADH : poor substrate binding )

Acetone + NAD+    ==(ADH) ===> No reaction      ( No binding )