Introduction to Enzymes

1. What is the relationship (an equation) of ΔG&ddeg;' to K_eq?
2. What is the relationship (use a statement) of ΔG^† to k for a reaction and, therefore, to rate?
3. What interactions help to promote formation of an ES complex?
4. What are the different types of co-factors? What is a distinguishing feature of each type?
5. What are the different classes of enzymes, and how can you identify each type?
6. What is an active site, and what are active site characteristics?
7. What are the mechanisms by which enzymes catalyze reactions, and what is a distinguishing characteristic of each mechanism?

Enzyme Kinetics

1. What observation led to derivation of the Michaelis-Menton equation as a description of enzyme behavior? What type of curve is described by the Michaelis-Menton equation?
*2. What are the simplifications and assumptions made during derivation of the equation, and why are they important?
3. Why is k_cat/K_M important?
4. Which enzyme characteristic –K_M and/or V_max–does each type of reversible inhibitor affect, and what is the effect?
*5. For each type of reversible inhibition, what is the appearance of a Lineweaver-Burk plot, and why?
6. What is the Michaelis-Menton equation, and what does each term in the equation mean?
7. How is K_M determined? How is V_max determined?
*8. What is the Lineweaver-Burk plot, and why is it significant?
9. What is k_cat (how is it defined)?
10. What are the different types of reversible enzyme inhibitors, and to what part of E or ES does each bind?
11. What are the classes of bi-substrate enzymes, and how are they different from each other?

Enzyme Catalysis

1. What is a serine protease, and what mechanism(s) does it use to catalyze proteolysis? How can you distinguish one transition state from another, and what happens to (a) produce the first transition state and (b) produce the second transition state?

*2. How are the mechanisms used by enolase and carbonic anhydrase similar? How are the enzymes different?

*3. What is the catalytic triad of a serine protease, and what type of bi-substrate reaction does a serine protease catalyze? What kinetic studies provide evidence for mechanisms? What are the specificity pocket and the oxyanion hole, and how are they involved in the reaction?

4. What is a kinase, and what mechanism(s) does hexokinase use to catalyze its reaction?

5. What reaction is catalyzed by enolase, and what co-factor(s) and active site residues are required?
6. What reaction is catalyzed by carbonic anhydrase, and what co-factor(s) and active site residues are required?

1. What are isozymes, and what is their function in enzyme regulation?

2. How does enzyme regulation occur using proteolysis? What are the advantages and disadvantages of using this method of regulation?
3. How does enzyme regulation occur covalently? What are the advantages and disadvantages of using this method of regulation?

4. How does enzyme regulation occur allosterically? What are the advantages and disadvantages of using this method of regulation?

5. What two types of enzymes are needed for the most common type of covalent regulation? How do these enzymes recognize their protein substrates, and how does modification affect the substrates?

1. What is the characteristic structure of a carbohydrate? What is an anomeric carbon, and why is it important?

2. How are disaccharides and polysaccharides formed? How do similar disaccharides differ from each other?

3. What are the major components of a nucleotide? How do nucleotides differ?

4. What is the important characteristic that defines a lipid? What are the different classes of lipids?

5. How are phospholipids and sphingolipids alike? How are they different? How is their relationship to water related to their function?

6. How are triacylglycerols, steroids, and eicosanoids alike? How are they different?

7. What are the ring and chain forms of D-glucose? How are the structures of D-fructose different?
8. What is a reducing sugar? What is the non-reducing end of a disaccharide?

9. What is the structure of ribose? How is deoxyribose different? How can you identify adenine, guanine, cytosine, thymine, and uracil?

10. What are the characteristics of fatty acids? How is the structure of a triacylglycerol different from the structure of a phospholipid?

top of page