CHEM 281: FUNDAMENTAL BIOCHEMISTRY
Review 4
1.
What are enzymes?
2.
Characteristic features of Enzyme-catalyzed reaction.
3.
What is the substrate for the enzyme: Pyruvate decarboxylase?
4.
What is the biophysical base for the high reaction rate of enzyme-catalyzed reaction?
5.
Definition: Enzyme-substrate complex, activation energy, transition state.
6.
Two enzyme-substrate binding models.
7.
Holoenzymes, apoenzymes, coenzymes, isoenzymes (isozymes) and zymogens
8.
NAD+ and NADH
9.
How NAD+ molecule carries electrons (and hydrogen) during dehydrogenation reaction?
10.
The effects of temperature and pH on enzyme activity.
11.
Active site (substrate binding site)
12.
What characteristic of competitive inhibition has?
13.
What is the activation energy of a reaction?
14.
Allosteric enzymes have an effector (modulator) binding site, as well as an active site.
Effector binding renders the enzyme active (__________) or inactive (___________).
15.
Michaelis-Menten Equation
16.
Michaelis-Menten plot of enzyme kinetics.
17.
Why are some enzymes being synthesized as inactive zymogens?
18.
Familiarize with the free energy/reaction coordination diagram of enzyme reaction.
An enzyme-catalyzed reaction is mediated through an unstable transition state. This may
involve the enzyme putting “stress” on a bond, bringing reactants into close proximity and in the
correct orientation, or altering the local pH.
Cofactors (coenzymes) are metal ions, organic compounds, or organometallic compounds that
bind to an enzyme and help maintain the correct configuration of the active site. The term
coenzyme refers specifically to an organic group that binds transiently to the enzyme during the
reaction. It accepts or donates chemical groups.
Enzymes are the biological catalysts of cells. They lower the activation energies but not alter the
equilibrium constant of the reactions they catalyze.