Chapter 8 Homework
Terms in this set (6)
What does an apoenzyme require to become a holoenzyme?
An apoenzyme requires a coenzyme to become a holoenzyme.
What is the fundamental mechanism by which enzymes enhance the rate of chemical reactions?
The main mechanism enzymes use to enhance the rate of chemical reactions is by quickly achieving or lowering the activation energy needed to enter the transition state. It accelerates the ability to reach equilibrium.
Proteins are thermodynamically
unstable. The delta G of the hydrolysis of proteins is quite negative, yet proteins can be quite stable. Explain this apparent paradox. What does it tell you about protein synthesis?
This tells me that energy is needed to synthesize proteins. The protein has a high activation energy.
So match the Keq with the appropriate delta G values.
From this work we can see that the closer Keq is at 1 the closer it is to equilibrium. So:
1=0 delta G
10^-5 = 28.8
10^4 = -22.84
10^2 = -11.42
10^-1 = 5.69
Assume that you have a solution of 0.1 M glucose 6-phosphate. To this solution, you add the enzyme
phosphoglucomutase, which catalyzes the following reaction:
Glucose 6-phosphate 3<:::::::::::>4 glucose 1-phosphate
The Delta G for the reaction is +7.5 kJ mol (11.8 kcal mol).
(a) Does the reaction proceed as written? If so, what are the final concentrations of glucose 6-phosphate and glucose 1-phosphate?
(b) Under what cellular conditions could you produce glucose 1-phosphate at a high rate?
So to determine this question you must decipher the following:
a) First thing you want to do is to determine the concentrations of the products and the reactants and if the products are larger than the reactants then the reaction will not work.
b) This would only work if there was a mechanism of supplying energy in the form of GTP or ATP to allow the reaction to start since this is an endothermic reaction.
What is the biochemical advantage of having a KM approximately equal to the substrate concentration normally available to an enzyme?
The biochemical advantage of having the Km approximately equal to the substrate concentration is to not have an overload of catalyzed reaction, there needs to be a balance maintained.