BICH 409 EXAM 2 QUESTIONS WITH VERIFIED
ANSWERS
How do you find kcat given enzyme concentration and vmax? - answers - kcat = vmax /
[e]
Which of the enzymes listed requires nad/nadh as a cofactor?
- liver alcohol dehydrogenase
- rna nuclease
- carbonic anhydrase
- all of these
- elastase - answers - - liver alcohol dehydrogenase
What makes up the serine protease catalytic traid? - answers - asp, ser, and his
Which of the enzymes listed accelerate the reactions by covalent catalysis?
- elastase
- rna nuclease
- carbonic anhydrase
- liver alcohol dehydrogenase
- all of these - answers - - elastase
A transition state analog would serve as an effective:
- allosteric inhibitor
- competitive inhibitor
- noncompetitive inhibitor
- mixed noncompetitive inhibitor
- irreversible inhibitor - answers - - competitive inhibitor
Which statement is not characteristic of allosteric enzymes?
- they frequently catalyze the first committed step in a biosynthetic pathway.
- they are composed of subunits.
- they cooperatively bind substrates.
- they follow michealis-menten kinetics.
- the binding of positive allosteric effectors results in an increase in enzyme activity. -
answers - - they follow michaelis-menten kinetics
Serine protease reaction mechanisms involve:
- covalent catalysis only.
- general acid-base and covalent catalysis.
- general acid/base catalysis only.
- specific acid/base catalysis only.
, - electrostatic catalysis only. - answers - - general acid-base and covalent catalysis
Which of the enzymes listed contain 2 essential histidine residues which function in
general acid/base catalysis?
- elastase
- liver alcohol dehydrogenase
- all of these
- carbonic anhydrase
- rna nuclease - answers - rna nuclease
Which of the enzymes is a serine protease?
- rna nuclease
- all of these
- carbonic anhydrase
- elastase
- liver alcohol dehydrogenase - answers - - elastase
Which of the following statements about the km is correct?
- km has units of concentration-1.
- km is dependent on the enzyme concentration.
- km is a measure of the affinity of the enzyme for the substrate.
- km is always much less than the substrate concentration.
- km is always equal to the substrate dissociation constant. - answers - - km is a
measure of the affinity of the enzyme for the substrate.
The steady state assumption, as applied to enzyme kinetics, implies that:
- the km is equal to the ks.
- the initial velocity is zero-order with respect to the substrate concentration.
- the reaction is at equilibrium.
- the substrate concentration is equal to the km.
- the rate of es formation is equal to the rate of the break down of es. - answers - - the
rate of es formation is equal to the rate of the break down of es.
What effect does a pure noncompetitive inhibitor have on km and vmax? - answers - -
leads to a decrease in observed vmax
- no effect on km
When given a table with kcat and km, how do you determine which enzyme has the
highest affinity for its substrate? - answers - the enzyme with the lowest km
When given a table with kcat and km, how do you determine which enzyme has the
highest efficiency at low substrate concentration? - answers - the greatest value for
kcat/km
Which side chain of the following amino acids is the least likely to act as a nucleophile?
ANSWERS
How do you find kcat given enzyme concentration and vmax? - answers - kcat = vmax /
[e]
Which of the enzymes listed requires nad/nadh as a cofactor?
- liver alcohol dehydrogenase
- rna nuclease
- carbonic anhydrase
- all of these
- elastase - answers - - liver alcohol dehydrogenase
What makes up the serine protease catalytic traid? - answers - asp, ser, and his
Which of the enzymes listed accelerate the reactions by covalent catalysis?
- elastase
- rna nuclease
- carbonic anhydrase
- liver alcohol dehydrogenase
- all of these - answers - - elastase
A transition state analog would serve as an effective:
- allosteric inhibitor
- competitive inhibitor
- noncompetitive inhibitor
- mixed noncompetitive inhibitor
- irreversible inhibitor - answers - - competitive inhibitor
Which statement is not characteristic of allosteric enzymes?
- they frequently catalyze the first committed step in a biosynthetic pathway.
- they are composed of subunits.
- they cooperatively bind substrates.
- they follow michealis-menten kinetics.
- the binding of positive allosteric effectors results in an increase in enzyme activity. -
answers - - they follow michaelis-menten kinetics
Serine protease reaction mechanisms involve:
- covalent catalysis only.
- general acid-base and covalent catalysis.
- general acid/base catalysis only.
- specific acid/base catalysis only.
, - electrostatic catalysis only. - answers - - general acid-base and covalent catalysis
Which of the enzymes listed contain 2 essential histidine residues which function in
general acid/base catalysis?
- elastase
- liver alcohol dehydrogenase
- all of these
- carbonic anhydrase
- rna nuclease - answers - rna nuclease
Which of the enzymes is a serine protease?
- rna nuclease
- all of these
- carbonic anhydrase
- elastase
- liver alcohol dehydrogenase - answers - - elastase
Which of the following statements about the km is correct?
- km has units of concentration-1.
- km is dependent on the enzyme concentration.
- km is a measure of the affinity of the enzyme for the substrate.
- km is always much less than the substrate concentration.
- km is always equal to the substrate dissociation constant. - answers - - km is a
measure of the affinity of the enzyme for the substrate.
The steady state assumption, as applied to enzyme kinetics, implies that:
- the km is equal to the ks.
- the initial velocity is zero-order with respect to the substrate concentration.
- the reaction is at equilibrium.
- the substrate concentration is equal to the km.
- the rate of es formation is equal to the rate of the break down of es. - answers - - the
rate of es formation is equal to the rate of the break down of es.
What effect does a pure noncompetitive inhibitor have on km and vmax? - answers - -
leads to a decrease in observed vmax
- no effect on km
When given a table with kcat and km, how do you determine which enzyme has the
highest affinity for its substrate? - answers - the enzyme with the lowest km
When given a table with kcat and km, how do you determine which enzyme has the
highest efficiency at low substrate concentration? - answers - the greatest value for
kcat/km
Which side chain of the following amino acids is the least likely to act as a nucleophile?
