Your colleague discovered a potential small molecule reversible inhibitor of the enzyme.  How would you set up an experiment to determine the type of inhibition this small molecule has on the enzyme?  

Using chemical structures and a reaction mechanism to illustrate your answer, provide an example of concerted acid-base catalysis in enzyme catalysis AND briefly explain why this is not possible in the absence of an enzyme.

a. What are the steps/characteristics of lysosome centered protein degradation? Discuss any specificities and give an example of at least one protein which is cleared via the lysosomal degradation.

  

b. What are the steps in the proteasome centered protein degradation via ubiquitination? Include the labeling with ubiquitin and the steps in proteasome and post proteasome processing. Discuss any specificities and give an example of at least one protein which is degraded via ubiquitination and the proteasome.

  

iv) Protein degradation may also be a way of regulating enzyme activities. What is an example of regulation of a key enzyme of a pathway where a product or effector regulates enzyme activity by increasing or decreasing the rate of degradation of the enzyme protein?

1. Briefly explain the regulation of gluconeogenesis and glycolysis by fructose 2,6-bisphosphate (F-2,6-BP) and how its concentration ismediated by insulin and glucagon.

5.Consider the regulation of glycolysis, gluconeogenesis, pyruvate dehydrogenase, and the TCA cycle, how is the regulation of these pathways linked to thermodynamics? How are they linked to one another?

Explain what is meant by the following statement: “Gluconeogenesis and glycolysis are reciprocally regulated.”

a. Detail the regulation of the unique enzymes found in each pathway in terms of metabolism

What is the purpose and/or products of the following steps?

Question 1 options:

_______________________ are stripped from the intermediate organic molecules of the Krebs Cycle.

carbon and hydrogen atoms

oxygen and electrons

H+ and electrons

ATP and NAD

In aerobic respiration NADH and FADH2 are oxidized back into NAD⁺ and FAD by

glycolysis.

the Krebs Cycle.

the electron transport chain.

fermentation.

Two ATP are used to add two phosphate groups to glucose in the

Krebs Cycle.

electron transport chain.

glycolysis.

bridge step.

ATP and ________________ is/are the product(s) from the Krebs Cycle.

NADH

FADH2 and NADH

NADH and carbon dioxide

NADH, FADH2 and carbon dioxide

NADH, FADH2, carbon dioxide and oxygen

1. Binding energy between an enzyme and a substrate contributes to catalysis in which way?

A. Binding energy provides the enzyme specificity for the substrate

B. binding energy contributions allow for entropy reduction in the substrate-enzyme complex

C. binding energy compensates for energy changes as a result of desolvation of the substrate

D. binding energy contributes to the process of induced fit between the substrate and the enzyme

E. all of the above are correct

2. a reaction is spontaneous if..

A. the transition state has higher free energy that the substrate

B. the product has lower free energy that the substrate

C. it proceeds rapidly and without a catalyst

D. it can proceed in only on direction

3. the enzyme Pepsin is produced in the stomach lining initially as a _______, which requires _______ for activation in the stomach.

A. Kinase; phosphorylation

B. zymogen; irreversible proteolytic cleavage

C. proprotein; reversible proteolytic cleavage

D. zymogen; ubiquitination

E. phosphorylase; irreversible proteolytic cleavage