1st Flashcards
A competitive inhibitor of an enzyme is usually
structurally similar to the substrate
Linear inhibition is sometimes called as
complete inhibition
The types of inhibition pattern based on
Michaelis Menten equation are
competitive
non-competitive
uncompetitive
The effect of non-competitive inhibition on a
Lineweaver-Burk Plot is that
it can change the y-intercept
The rate-determining step of Michaelis Menten
kinetics is
the complex dissociation step to produce
product
In competitive inhibition a factor is obtained
from the measurement of
KM
Which of these proteases is not a cysteine active
site protease?
Cathepsin D
Given an enzyme with a Km = 10m M and Vmax = 100 m mol/min. If [S] = 100 m M, which of the following will be true?
A 10-fold increase in Vmax would increase
velocity 10-fold y
The conformational change in an enzyme after the substrate is bound that allows the chemical reaction to proceed, can be explained by
induced fit
The active site of an enzyme remains
a. at the center of globular proteins
b. rigid and does not change shape
c. complementary to the rest of the molecule
d. none of the above
Which category of enzymes belongs to class two in the international classification?
Transferases
The reciprocal equation for non-competitive inhibition can be arranged to the equation for the
Dixon plot
The Woolf-Augusteinsson-Hofstee plot of ν versus ν/[S] and the Eadie-Scatchard plot of ν/[S] versus ν do not involve reciprocals of ν therefore are considered to be more reliable when the error in v is
significant
The relationship between Keq, Km and Vmax is
known as
Haldane equation
Which of the following statements is true for enzymatically catalyzed reaction
The activation energy of the reaction is lowered so that a larger proportion of the substrate qualifies to overcome it
Which of the following common drugs is not a
specific enzyme inhibitor
Iodine
The enzyme inhibition can occur by
reversible inhibitors
irreversible inhibitors
In a Lineweaver-Burk Plot, competitive inhibitor shows which of the following effect?
It changes the x-intercept
Which of the following statements is not true?
a. Enzymes are proteins that bind to specific
substrates and increase the velocity of
reactions involving those substrates
b. Enzymes function by overcoming the
activation energy barrier of a reaction
c. Enzymes make thermodynamically
favorable reactions to proceed; they cannot
make unfavorable reactions to occur
d. Enzymes only function when they are in
intact cells
Non-competitive inhibitor of an enzyme
catalyzed reaction
decreases Vmax
binds to Michaelis complex (ES)
An enzyme and a reactant molecule maintain
relationship as
a temporary association
The plot commonly used for determining the
value of Vmax is
Lineweaver Burk plot Langmuir plot
Eadie Hofstee plot
Quasi steady state is also known as
Pseudo steady state
Which of these enzymes contains a Zinc (Zn)
ion?
a. Carboxypeptidase A (?)
b. Phosphorylase B kinase
c. Tyrosine hydroxylase
d. Phosphodiesterase
A noncompetitive inhibitor of an enzymecatalyzed reactio
increases KM and reduces Vmax
An allosteric inhibitor of an enzyme usually
participates in feedback regulation
Which of the following activity is possible by
transferases?
a. Transfer of methyl groups
b. Transfer of glycosyl group
A classical uncompetitive inhibitor is a
compound that binds
reversibly to the enzyme substrate complex yielding an inactive ESI complex
Which graphical method is used to determine an enzyme degree of cooperativity?
Hill plot
