ProblemSet8 - base catalysis. Why isnt glycine among those...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 114A Practice Problems Chapter 11: 1. Explain why enzymes are stereospecific? 2. What is an apoenzyme and hoe does it differ from a holoenzyme? Which form is active? 3. What is the relationship between vitamins and coenzymes? 4. What is the rate-determining step of an enzyme-catalyzed reaction? 5. Answer yes or no to the following questions and explain your answer. a) Can the absolute value of G for a reaction be larger than + G (free energy of activation)? b) Can + G for an enzyme-catalyzed reaction be greater than + G for the nonenzymatic reaction? c) In a two step reaction, such as the one diagrammed in Fig.11-6, must the intermediate (I) have less free energy than the reactant (A)? d) In a multistep reaction, does the transition state with the highest free energy always correspond to the rate-determining step? 6. An increase in temperature increases the rate of a reaction. How does the temperature affect + G ? 7. List the amino acid residues that are most likely to participate in general acid-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: base catalysis. Why isnt glycine among those listed? 8. If a protonated His residue acts as the proton donor in an acid-catalyzed enzymetic reaction, what happens to the enzymes activity as the pH increases to a value that exceeds the pK R of that residue? 9. The pK values of two essential catalytic residues in RNase A are 5.4 and 6.4. Which corresponds to His 12 and which to His 119? 10. What is the difference between nucleophilic catalysis and general base catalysis? 11. A good covalent catalyst is highly nucleophilic and can form a good leaving group. What structural properties support these seemingly opposite characteristics? 12. Classify each of the following groups as an electrophile or nucleophile: a) amine b) carbonyl c) cationic imine d) hydroxyl e) imidazole 13. What is the role of Zn 2+ in carbonic anhydrase? 14. How hoes lysozyme destroys bacterial cell walls?...
View Full Document

This note was uploaded on 01/31/2010 for the course CHEM chem 114A taught by Professor Gourisankarghosh during the Fall '06 term at UCSD.

Page1 / 2

ProblemSet8 - base catalysis. Why isnt glycine among those...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online