ENZYMOLOGY Flashcards
What is a coenzyme?
Organic molecules
A coenzyme or metal ion that is very tightly or even covalently bound to the enzyme is called?
Prosthetic group
complete catalytically active enzyme together with its bound coenzyme is called
Holoenzyme
The protein part of holoenzyme is called?
Apoenzyme
Which suffix is added to the name of the substrate or to a word or to a phrase describing the activity of enzyme, to name an enzyme?
-Ase
Which enzyme transfers phosphate groups?
Hexokinase
The site where enzyme catalyzed reaction takes place is called?
Active Site
The molecule that is bound and acted upon by the enzyme is called?
Substrate
Who proposed the existence of proteolytic enzymes as proteins?
Northrop
What will happen to the enzyme-catalyzed reaction if temperature is increased?
Rate of reaction increases
What will happen to reaction if more enzymes are added?
Rate of reaction increase
How metal ions participate in catalysis?
By causing reduction and oxidation reactions between enzyme and substrate
By causing ionic interactions between enzyme and substrate
What is Vmax
Maximum rate of reaction
What is Km in Michaelis-Menten Equation?
Michaelis-Menten constant
Which enzymes are said to follow Michaelis-Menten kinetics?
a. Enzymes which show parabolic dependence of rate of reaction and substrate
b. Enzymes which show circular dependence of rate of reaction and substrate
c. Enzymes which show hyperbolic dependence of rate of reaction and substrate
d. None of the above
Enzymes which show hyperbolic dependence of rate of reaction and substrate
Double-reciprocal plot is also called?
Line plot
Which scientist proposed lock and key model in 1894?
Emil Fisher
What is induced fit?
a. when enzyme change shape due to absence of substrate
b. when enzyme do not change shape due to absence of substrate
c. when enzyme change shape due to presence of substrate
d. when enzyme do not change shape due to presence of substrate
when enzyme change shape due to presence of substrate
Who postulated induced fit in year1958?
Daniel Koshland
A purely competitive enzyme inhibitor has which of the following kinetic effects?
increases Km without affecting Vmax
Enzymes as classic catalysts accomplish which of the following energy effects?
lower the energy of activation
Synthesis of an enzyme promoted by the substrate on which it acts, is characterized by the term
Induction
Which statement about the active site is incorrect?
A. It is composed of linearly arranged amino acid chain.
B. It is relatively small compared to the total bulk of the enzyme.
C. It does not generally form covalent interaction with substrates.
D. It is three-dimensional in quality.
E. none of these
It is composed of linearly arranged amino acid chain.
Which statement about most enzymes is incorrect?
A. They increase the rapidity of the reactions they catalyze.
B. They are specific for the substrate as well as the reaction catalyzed.
C. They are large polypeptides with high molecular weight.
D. They are most active near neutral pH.
E. They are not affected by changes in temperature.
They are not affected by changes in temperature.