Biochem 3G03 Test 4

A protein contains two 60-kD polypeptides and two 30-kD polypeptides. Each 30-kD chain associates with a 60-kD chain noncovalently. The 90-kD units associate covalently via disulfide bond between the two 30-kD chains to form a protein with a molecular mass of 180 kD. Which of the followings is not correct? (a) Molecular mass determined by gel filtration is 180 kD (b) Molecular mass determined by SDS-PAGE is 90 kD (c) PAGE shows one single band (d) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 30kD and 60 kD (e) All answers are correct

(b) Molecular mass determined by SDS-PAGE is 90 kD

E. coli's RNA polymerase holoenzyme contains 6 polypeptides: two identical 95-kD alpha subunit, one 65-kD beta subunit, one 60-kd beta' subunit, one 20-kD omega subunit and one 70-kD Sigma subunit. The two alpha subunits are linked to each other by disuphide bond. The beta and beta' subunits are also linked to each other by disulphide bond. The enzyme was extracted from a complex mid-way through transcription with complete removal of DNA and RNA. Which of the followings is correct? (a) Molecular mass determined by SDS-PAGE without 2-mercaptoethanol are 190, 125, 70 and 20 kD (b) Molecular mass determined by gel filtration is 405 kD (c) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 95, 70, 65, 60 and 20 kD (d) PAGE shows one single band (e) All answers are correct

(d) PAGE shows one single band

A protein contains two 60-kD polypeptides and two 30-kD polypeptides. Each 30-kD chain associates with a 60-kD chain covalently via disulfide bond. The 90-kD units associate noncovalently to form a protein with a molecular mass of 180 kD. Which of the followings is not correct? (a) Molecular mass determined by (b) Molecular mass determined by SDS-PAGE is 90 kD (c) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 30kD and 60 kD (d) PAGE shows one single band (e) All answers are correct

(e) All answers are correct

A protein contains two 60-kD polypeptides and two 40-kD polypeptides. Each 40-kD chain is disulfide bonded to a 60-kD chain. The 100-kD units associate covalently with disulfide bond to form a protein with a molecular mass of 200 kD. Given 2-mercaptoethanol can reduce disulfide bond, which of the followings is not correct? (a) Molecular mass determined by gel filtration is 200 kD (b) Molecular mass determined by SDS-PAGE without 2-mercaptoethanol is 200 kD (c) PAGE shows one single band (d) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 40kD and 60 kD (e) All answers are correct

(e) All answers are correct

4. ____ forms microfilaments in cells. a) Actin b) Tubulin dimers c) Keratin filaments d) Collagen e) Myoglobin

a) Actin

12. What amino acid performs the nucleophilic attack during the thrombin catalyzed reaction? a) Ser b) His c) Lys d) Asp e) Thr

a) Ser

8. What amino acid performs the nucleophilic attack during the chymotrypsin mechanism? a) Ser b) His c) Lys d) Asp e) Thr

a) Ser

22. In the chymotrypsin mechanism, which of the following is most likely correct? a) The pKa of Ser 195 is lowered by the combined effect of Asp 102 and His 57 b) The pKa of His 57 is lowered by Asp 102 c) His 57 is a nucleophile d) Ser 195 is an acid-base catalyst e) Ser 195 acts as an acid catalyst by donating its hydrogen to His 57

a) The pKa of Ser 195 is lowered by the combined effect of Asp 102 and His 57

15. In an enzyme mechanism that generates a negative charge in the transition state, which of the following would be beneficial to have in the active site of the enzyme? a) a positive charge b) an Asp residue c) an Gln residue d) a negative charge e) none of the above

a) a positive charge

10. Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state? a) all four subunits switch simultaneously b) each subunit switches only upon oxygen binding to the particular subunit c) both alpha subunits simultaneously switch first followed by both beta subunits d) both beta subunits simultaneously switch first followed by both alpha subunits e) none of the rest

a) all four subunits switch simultaneously

6. What is the most prevalent secondary structure observed in the proteins of intermediate filaments? a) alpha-helices b) beta-helices c) alpha-sheets d) beta-sheets e) both alpha-helices and beta-helices are observed

a) alpha-helices

9. Bone and tendons contain _____ while hair and nails contain _____. a) collagen; keratin b) actin; keratin c) tubulin; collagen d) collagen; actin e) tubulin; keratin

a) collagen; keratin

17. The enzyme hexokinase catalyzes a reaction where its substrates are completely sequestered from the aqueous environment allowing for interactions to occur between enzyme and substrates that would not normally occur in an aqueous environment. What term describes this type of catalysis? a) electrostatic catalysis b) desolvation catalysis c) non-aqueous catalysis d) hydrogen-bonded catalysis e) closed-system catalysis

a) electrostatic catalysis

14. In the chymotrypsin mechanism, what is used to stabilize the negative charge on the carbonyl oxygen of the transition state? a) hydrogen bonding between the enzyme and the anion from the carbonyl oxygen b) electrostatic interaction of the positively charged His and carbonyl oxygen c) electrostatic interaction of the negatively charged Asp and carbonyl oxygen d) electrostatic interaction of the active site Zn2+ and carbonyl oxygen e) all of the rest

a) hydrogen bonding between the enzyme and the anion from the carbonyl oxygen

15. How does a catalyst affect the overall delta-G of an endergonic reaction? a) it has no effect b) the reaction becomes more endergonic c) the reaction has a delta-G of zero d) the reaction becomes exergonic e) none of the rest

a) it has no effect

20. Which of the following is true regarding heparin? a) it is an allosteric activator of antithrombin b) it is a phosphated polysaccharide c) it simultaneously binds to antithrombin and fibrin d) it is used clinically as a coagulant e) all of the rest

a) it is an allosteric activator of antithrombin

10. In an enzyme mechanism that generates a negative charge in the transition state, which of the following would be most advantageous to have in the active site of the enzyme? a) transition metal cation b) Asp residue c) Gln residue d) transition metal anion e) none of the rest

a) transition metal cation

1. Which element has the highest electronegativity? a) Carbon b) Fluorine c) Hydroen d) Nitrogen e) Oxygen

b) Fluorine

11. Which amino acid is critical for crosslinking of collagen trimers? a) Ser b) Lys c) His d) Cys e) Gln

b) Lys

2. Which of the following statements does not apply to collagen? a) It contains hydroxylated amino acids. b) One single polypeptide forms a right-handed helix. c) Cross-links between neighbouring Lys residues stabilize the helix. d) Glycine at every third position is essential for the stability of the triple helical structure. e) The triple helical structure twists in the right-handed direction.

b) One single polypeptide forms a right-handed helix.

13. Acetoacetate decarboxylase catalyzes the decarboxylation of acetoacetate via formation of Schiff base between the ketone of acetoacetate and its Lys 115 (Fig.4). Which of the following best describe this catalysis? a) acid-base catalysis b) covalent catalysis c) electrophilic catalysis d) metal ion catalysis e) none of the rest

b) covalent catalysis

8. An enzyme that forms a covalent bond with its substrate during the course of a reaction is considered to undergo _____. a) acid-base catalysis b) covalent catalysis c) electrophilic catalysis d) metal ion catalysis e) none of the rest

b) covalent catalysis

If aspartic acid (pKa=3.90) is being used by an enzyme that catalyzes the conversion of a ketone to an enol by acid catalysis; which of the following would be most advantageous to have in the vicinity of the active site aspartic in a pH=7 environment? a) alanine b) glutamic acid c) histidine d) arginine e) histidine

b) glutamic acid

18. The ability for an enzyme to change its shape upon substrate binding represents the concept of _____. a) lock and key b) induced fit c) proximity and orientation effects d) covalent catalysis e) none of the above

b) induced fit

5. If 20% of the DNA in a relaxed circular-covalently-closed plasmid is induced to change from B-DNA to Z-DNA and then treated by an enzyme that has type IA topoisomerase activity, what happens to the value of the linking number? a) decreases b) remains the same c) none of the answers d) increases e) cannot be calculated without knowing the size of the plasmid

b) remains the same

9. Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules? a) both alpha and beta sites are bound to GTP b) the alpha site is bound to GTP; the beta site is bound to GDP c) the alpha site is bound to GDP; the beta site is bound to GTP d) both alpha and beta sites are bound to GDP e) the alpha site is bound to GTP; the beta site is unoccupied following GTP hydrolysis and release of GDP

b) the alpha site is bound to GTP; the beta site is bound to GDP

3. At pH ___, the pentapeptide Ala-Glu-His-Val-Cys would contain two positively charged groups and two negatively charged group. a) 1 b) 3 c) 5 d) 7 e) 9

c) 5

4. During the formation of microfilaments, which of the following occurs? a) ATP binds to F-actin b) F-actin polymerizes, becoming G-actin c) ATP hydrolysis is catalyzed by F-actin d) polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized e) none of the rest

c) ATP hydrolysis is catalyzed by F-actin

11. What three amino acids are found in the catalytic triad of prothrombin? a) Glu, His, Thr b) Ser, Arg, Cys c) Asp, His, Ser d) Cys, Lys, Glu e) Asn, His, Thr

c) Asp, His, Ser

7. What three amino acids are found in the catalytic triad of chymotrypsin? a) Glu, His, Thr b) Ser, Arg, Cys c) Asp, His, Ser d) Cys, Lys, Glu e) Asn, His, Thr

c) Asp, His, Ser

23. Chymotrypsin has a large specificity pocket to bind the aromatic amino acids while elastase has a very small specificity pocket meant to bind Ala or Gly. Which of the following amino acid substitutions changes the specificity pocket of chymotrypsin to that of elastase? a) Trp to Ser b) Leu to Ala c) Gly to Val d) Lys to Asp e) Val to Asn

c) Gly to Val

5. _________ constitute the bulk of animal hair. a) Actin b) Tubulin dimers c) Keratin filaments d) Collagen e) Myoglobin

c) Keratin filaments

16. In the enzyme catalyzed decarboxylation of acetoacetate (Figure 2), a Schiff base is formed between the ketone of acetoacetate and a _____ residue in the active site of the enzyme. a) Arg b) Asn c) Lys d) Glu e) Ser

c) Lys

4. A plasmid with 4000 bp of closed circular duplex DNA was isolated from E. coli. It has a 300-bp segment of alternating C and G residues. Upon transfer to a high salt solution, this segment undergoes a transition from the B conformation to the Z conformation. Which of the followings is correct after this plasmid is further treated with a type IB topoisomerase that is active at the high salt solution? a) Its original linking number is 400 b) The change in its writhing number is 55 c) The change in its twist is -55 d) Its linking number is not changed e) All answers are correct

c) The change in its twist is -55

2. Which of the structures in Figure 5 shows the prevalent form of aspartic acid at pH 3? (2014) a) a b) b c) c d) d e) e

c) c

25. Which of the following represents a rapid and reversible mechanism to alter the activity of an enzyme? a) synthesis of more enzyme to increase activity b) degradation of enzyme to decrease activity c) covalent attachment of a phosphate group to increase or decrease activity d) movement of an enzyme from one cellular compartment to another e) none of the rest

c) covalent attachment of a phosphate group to increase or decrease activity

7. According to Table 1, Chymotrypsin catalyzes the hydrolysis of a peptide bond and is therefore categorized as a _____. a) oxidoreductase b) transferase c) hydrolase d) lyase e) ligase

c) hydrolase

3. A globular protein has a _____ core and is stabilized primarily by the ________ effect. a) hydrophilic, hydrophilic b) hydrophobic, hydrophilic c) hydrophobic, hydrophobic d) hydrophobic, ion pairing e) ionic, ion pairing

c) hydrophobic, hydrophobic

11. Chymotrypsinogen is not enzymatically active because _____. a) it does not contain the cofactors required for catalysis b) it is the product of a mutated gene c) its active SITES are distorted and incapable of enzymatic activity d) the pH of its environment is not optimal for activity e) none of the rest

c) its active SITES are distorted and incapable of enzymatic activity

2. Myoglobin is _____; hemoglobin is _____. a) monomeric; dimeric b) monomeric; trimeric c) monomeric; tetrameric d) dimeric; trimeric e) dimeric; tetrameric

c) monomeric; tetrameric

9. Zymogens are not enzymatically active because _____. a) they do not contain the cofactors required for catalysis b) they are the product of mutated genes c) their active SITES are distorted and incapable of enzymatic activity d) the pH of their environment is not optimal for activity e) the pKa's of their active site residues are too low

c) their active SITES are distorted and incapable of enzymatic activity

Which of the following compounds has highest affinity to its cognate enzyme a) substrate b) allosteric inhibitor c) transition state d) product e) none of the answers

c) transition state

13. Of all the species that enzymes bind, they are thought to bind most tightly to _____. a) substrates b) products c) transition states d) intermediates e) all are bound very tightly

c) transition states

24. In a sample of hemoglobin at 300K, the ratio of deoxygenated to oxygenated states is 821:1. Given the gas constant R = 1.987 cal K-1 mol-1, and the Boltzmann Equation is p1/p2 = exp[(E2-E1)/RT] what is the difference in energy (kcal) between the two states of hemoglobin? a) 1 b) 2 c) 3 d) 4 e) 5

d) 4

A protein contains three 60-kD polypeptides and six 20-kD polypeptides. Each 60-kD chain is disulfide bonded to two 20-kD chains. The 100-kD units associate noncovalently to form a protein with a molecular mass of 300 kD. Which of the followings is correct? a) Molecular mass determined by gel filtration is 300 kD b) PAGE shows one single band c) Molecular mass determined by SDS-PAGE without 2-mercaptoethanol is 100 kD d) All answers are correct e) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 20kD and 60 kD

d) All answers are correct

7. How does CO2 affect hemoglobin-oxygen binding? a) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state b) CO2 displaces BPG, thus promoting the oxy state c) CO2 is converted to bicarbonate and H+ which promotes the oxy state d) CO2 is converted to bicarbonate and H+ which promotes the deoxy state e) none of the rest

d) CO2 is converted to bicarbonate and H+ which promotes the deoxy state

24. Which of the following proteins is/are zymogen(s)? a) Tissue factor b) Thrombin c) Fibrinogen d) Factor X e) None of the rest

d) Factor X

1. The central ion of the heme group of methemoglobin is _____. a) Cu(+) b) Cu(2+) c) Fe(2+) d) Fe(3+) e) none of these choices

d) Fe(3+)

17. Which of the following is most likely correct about reactions involving chymotrypsin and/or chymotrypsinogen? a) A comparison of the X-ray structures of chymotrypsin and chymotrypsinogen reveals that the conformations of their active site Asp, His, and Ser residues are rather different b) Chymotrypsinogen cannot catalyze hydrolysis at all c) The substrate specificity pocket in chymotrypsinogen is virtually the same as that in chymotrypsin d) The oxyanion hole in chymotrypsinogen is not formed properly e) Activation of trypsinogen by chymotrypsinogen is an example of autoactivation

d) The oxyanion hole in chymotrypsinogen is not formed properly

12. Acetoacetate decarboxylase catalyzes the decarboxylation of acetoacetate via formation of Schiff base between the ketone of acetoacetate and its Lys 115 (Fig.4). Which of the following is most likely correct? a) The measured pKa of Lys 115 is 10.54 b) Lys 115 is a potent electrophile c) The pKa of Lys 115 is independent of its microenvironment d) The perturbed pKa of Lys 115 is a result of interaction with Lys 116 e) The perturbed pKa of Lys 115 is a result of interaction with Glu 76

d) The perturbed pKa of Lys 115 is a result of interaction with Lys 116

13. Which of the following is the most effective way to increase the rate of a biochemical reaction? a) increase the temperature b) increase the concentrations of the reactants c) increase or decrease the pH d) add a catalyst e) none of the rest

d) add a catalyst

If lysine (pKa=10) is the nucleophile in acetoacetate decarboxylase participating in covalent catalysis, which of the following would be most advantageous to have in the vicinity of the active site lysine in a pH=7 environment? a) alanine b) glutamic acid c) histidine d) arginine e) histidine

d) arginine

5. All protein derived amino acids have L stereochemical configuration because a) they are all dextrorotatory b) they are all levorotatory c) they are all optically active d) configuration of groups on C-alpha can be related to that of L-glyceraldehyde e) none of the given reasons

d) configuration of groups on C-alpha can be related to that of L-glyceraldehyde

17. During the first half of the chymotrypsin mechanism where the acyl-enzyme intermediate is formed, what role does His play? a) general acid only b) general base only c) general acid then general base d) general base then general acid e) nucleophile

d) general base then general acid

15. NMR studies on serine protease catalyzed reactions suggest that ________ observed between the catalytic Asp and His helps stabilize the transition state. a) dipole-dipole interaction b) electrostatic interaction c) hydrogen bond d) low-barrier hydrogen bond e) covalent bond

d) low-barrier hydrogen bond

Pyruvate decarboxylase catalyzes the conversion of pyruvate to acetaldehyde and CO2. According to table 1, pyruvate decarboxylase is a a) oxidoreductase b) transferase c) hydrolase d) lyase e) Isomerase

d) lyase

2. The sequence of amino acids in a polypeptide can be determined by: a) high performance liquid chromatography b) size exclusion chromatography c) thin layer chromatography d) mass spectrometry e) magnetic resonance imaging

d) mass spectrometry

8. During the formation of microfilaments, which of the following occurs? a) ATP binds to F-actin b) F-actin polymerizes, becoming G-actin c) ATP hydrolysis is catalyzed by G-actin d) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed e) none of the rest

d) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed

14. Which of the following is seen in a reaction coordinate diagram for an enzyme-catalyzed reaction that uses covalent catalysis? a) two distinct intermediates b) one transition state c) reactants that are higher in energy than intermediate(s) d) products that are lower in energy than intermediate(s) e) all of the rest

d) products that are lower in energy than intermediate(s)

3. The individual hemoglobin subunits and myoglobin share similar _____ structure but have rather different _____ structure. a) primary; secondary b) secondary; tertiary c) primary; tertiary d) secondary and tertiary; primary e) primary and secondary; tertiary

d) secondary and tertiary; primary

10. The helical structure of collagen contains _____. a) three right-handed helices wound around each other in a right-handed triple helix b) three right-handed helices wound around each other in a left-handed triple helix c) three left-handed helices wound around each other in a left-handed triple helix d) three left-handed helices wound around each other in a right-handed triple helix e) none of the rest

d) three left-handed helices wound around each other in a right-handed triple helix

22. To make a phosphate buffer at pH 12.38 starting with one liter of 20 mM phosphoric acid (H3PO4; pKs are of 2.15, 6.82, and 12.38), you could add _____ mL of ____ M KOH a) 15; 4 b) 30; 3 c) 50; 2 d) 75; 1 e) 100 0.5

e) 100 0.5

23. At pH of 7, if the molecular weight of alanine is 89 daltons, what is the molecular weight of ala-ala-ala? a) 267 b) 249 c) 240 d) 235 e) 231

e) 231

1. At pH 8, how many charged groups are present in the pentapeptide ADHRSK? a) 1 b) 2 c) 3 d) 4 e) 5

e) 5

21. Which of the following is most likely incorrect? a) A comparison of the X-ray structures of chymotrypsin and chymotrypsinogen reveals that the conformations of their active site Asp, His, and Ser residues are virtually identical b) Zymogen can catalyze hydrolysis extremely slowly c) The substrate specificity pocket in chymotrypsinogen is incompletely formed d) The oxyanion hole in chymotrypsinogen is incompletely formed e) Activation of chymotrypsinogen by trypsinogen is an example of autoactivation

e) Activation of chymotrypsinogen by trypsinogen is an example of autoactivation

A protein contains three 60-kD polypeptides and six 20-kD polypeptides. Each 60-kD chain is disulfide bonded to two 20-kD chains. The 100-kD units associate noncovalently to form a protein with a molecular mass of 300 kD. Which of the followings is correct? a) Molecular mass determined by gel filtration is 300 kD b) Molecular mass determined by SDS-PAGE without 2-mercaptoethanol is 100 kD c) Molecular masses determined by SDS-PAGE with 2-mercaptoethanol are 20kD and 60 kD d) PAGE shows one single band e) All answers are correct

e) All answers are correct

Which of the following statements is true about carbonic anhydrase? a) It is found in most tissues b) It is particularly abundant in red blood cells c) It catalyzes the conversion of dissolved CO2 to bicarbonate in the tissue d) It catalyzes the conversion of bicarbonate to CO2 in the lung e) All of the rest are correct

e) All of the rest are correct

Activation of coagulation factor IX can be accomplished in vivo by a) Aggregation of inactive subunits b) Dissociation of inactive subunits c) Factor IXa alone d) Factor VIIa alone e) Factor VIIa and tissue factor

e) Factor VIIa and tissue factor

4. At pH _____ histidine is found mainly in form II of Figure 1. a) 1 b) 5 c) 7 d) 9 e) None of the given

e) None of the given

2. In the chymotrypsin mechanism, which of the following is most likely incorrect? a) The pKa of Ser 195 is lowered by the combined effect of Asp 102 and His 57 b) The pKa of His 57 is increased by Asp 102 c) His 57 is an acid-base catalysts d) Ser 195 acts as a nucleophile e) Ser 195 acts as an acid catalyst by donating its hydrogen to His 57

e) Ser 195 acts as an acid catalyst by donating its hydrogen to His 57

1. Acetoacetate decarboxylase catalyzes the decarboxylation of acetoacetate via formation of Schiff base between the ketone of acetoacetate and its Lys 115. Which of the following is most likely incorrect? a) The measured pKa of Lys 115 is 5.96 b) Lys 115 is a potent nucleophile c) The pKa of Lys 115 is perturbed by its microenvironment d) The perturbed pKa of Lys 115 is a result of interaction with Lys 116 e) The perturbed pKa of Lys 115 is a result of interaction with Glu 76

e) The perturbed pKa of Lys 115 is a result of interaction with Glu 76

22. Acetoacetate decarboxylase catalyzes the decarboxylation of acetoacetate via formation of Schiff base between the ketone of acetoacetate and its Lys 115 (Figure 2). Which of the following is most likely incorrect? a) The measured pKa of Lys 115 is 5.96 b) Lys 115 is a potent nucleophile c) The pKa of Lys 115 is perturbed by its microenvironment d) The perturbed pKa of Lys 115 is a result of interaction with Lys 116 e) The perturbed pKa of Lys 115 is a result of its contact with a phosphate anion

e) The perturbed pKa of Lys 115 is a result of its contact with a phosphate anion

Which of the following is a serine protease? a) Factor XIa b) Factor IXa c) Trypsin d) Subtilisin e) all listed are serine proteases

e) all listed are serine proteases

13. Which of the following is seen in a reaction coordinate diagram for an enzyme-catalyzed reaction that uses covalent catalysis? a) an intermediate b) two distinct transition states c) reactants that are lower in energy than an intermediate d) products that are lower in energy than an intermediate e) all of the rest

e) all of the rest

18. Which of the following is true regarding heparin? a) it is an allosteric activator of antithrombin b) it is a sulfated polysaccharide c) it simultaneously binds to antithrombin and the target of antithrombin d) it is used clinically as an anticoagulant e) all of the rest

e) all of the rest

21. Which of the following is a feature of protease inhibitor specific for trypsin? a) contains a positive charge to mimic the charge of the substrate b) ability to interact with the Ser of the catalytic triad c) inability to form the tetrahedral intermediate d) high affinity for the enzyme active site e) all of the rest

e) all of the rest

6. Which of the following can increase the rate of a biochemical reaction? a) increase the temperature b) increase the concentrations of the reactants c) increase or decrease the pH d) add a catalyst e) all of the rest

e) all of the rest

4. What is the prominent type of secondary structure observed in myoglobin? a) coiled-coil b) left-handed triple helix d) antiparallel beta-sheets e) alpha-helices

e) alpha-helices

5. The idea that binding of one molecule of oxygen to myoglobin enhances further binding of oxygen to myoglobin is called _____. a) homologous binding b) cooperativity c) fractional saturation d) allosterism e) none of the choices

e) none of the choices

25. Which of the following represents a rapid and reversible mechanism to alter the activity of an enzyme? a) synthesis of more enzyme to increase activity b) degradation of enzyme to decrease activity c) covalent attachment of a sulphate group to increase or decrease activity d) movement of an enzyme from one cellular compartment to another e) none of the rest

e) none of the rest

Enzymes differ from ordinary chemical catalysts in that their reactions: a) have slower reaction rates b) have a much reduced free energy of reaction c) often have side products d) have less specificity e) none of the rest

e) none of the rest

The lifetimes of transition states are extremely short, so most understandings of transition states were derived from a) fibre diffraction studies b) crystallographic studies c) NMR studies d) IR studies e) theoretical studies

e) theoretical studies