Exam 2 Flashcards
Oxidoreductases
Catalyzes Oxidation or Reduction RXN’s
Transfersases
Transfers functional groups between molecules
Hydrolases
Breaks bonds via addition of water
Lyases
Adds atoms/functional groups to double bonds or removes them to form double bonds
Isomerase
Moves functional groups within molecule
Ligases
Binds two molecules using ATP
apoenzyme
Enzyme without cofactor
Holoenzyme
Fully functional enzyme with cofactor
Two Types of Cofactors
Small Organic Molecules
-made up by vitamins (coenzymes)
Metals
Coenzymes
organic cofactors
Gibbs Free Energy
free energy difference between products and reactants (p-r)
- Gibbs Free Energy
Spontaneous RXN
Exergonic
+ Gibbs Free Energy
Energy required for RXN to take place
Endergonic
0 Gibbs Free Energy
RXN in equilibrium
2 Things Gibbs Free Energy does NOT do
- Give INFO about RXN rate
- Affected by intermediates of RXN
allosteric enxyme
enzyme with control mech.
Pathway Convergence
One RXN effecting another
Seqential Model
Substrate bonding effects rate of next substrate bonding
-Ex: Binding substrate at site 1, reduces affinity for substrate binding at site 2
Competitive Inhibition
-Molecule binds to an active site of enzyme and prevents substrate from bonding
MUST BIND TO ENZYME BEFORE SUBSTRATE BINDS
-Can be ‘washed’ out if lots of [S] added
Km = increases Vmax = unchanged
Uncompettitive Inhibition
-Molecule binds to enzyme substrate complex and prevents from going to product
MUST BIND TO ES COMPLEX
Km = decreases Vmax = decreases
Noncompetivie Inhibition
-Molecule binds to enzyme outside of enzyme substrate complex and prevents RXN
BINDS TO E OR ES COMPLEX
Km = no change Vmax = decreases
Psuedo First Order
A + B –> P
Acts as 1st order of A because so much excess of B
When [S] «_space;Km then?
V is proportional to [S]
Km Equation
Km= (K-1 + K2)/(K1)
Vo
Instantaneous Velocity
Vo=(Vmax)[S] / Km[S]
Vmax=
[ES]
Km on graph is found at?
Vmax over 2
Equation for Lineweaver Burke Plot
1/Vo = (Km/Vmax) (1/[S]) + (1/Vmax)
Definition of Vmax
Highest possible turnover rate of enzyme at full saturation
Vmax equation?
K2[E]t
Kcat?
Vmax
[E]t?
Total active sites
Normal Range of Km
10e-1 - 10e-7 M`
Km equation in vivo
Km = [S] @1/2 Vmax
@ Km, sensitive to what concentration?
substrate
Catalytic Efficiency Equation
CE = Kcat(K2) / Km
Pathway Convergence
One RXN’s product can influence another
Allosteric Enzymes are sensitive to changes in what near what?
Changes in [S] near the Km
Heterotrophic Effector Effect on enzyme curve
Shifts binding curve left or right
Homotrophic Effector
Alters shape of binding curve
T form does or does NOT prefer to form [ES] complex?
does NOT
Increase in [S] causes an increase or decrease in T and R forms
Increase in R state
Deacrease in T state
Competitive, non-competitive and uncompetive ARE reversible T/F?
TRUE
4 Uses of Carbs?
Energy storage, structure, cell surface recognition and binding, signal transduction
hemiacital
From aldehyde
Hemiketal
From ketone
Types of tests to determine if sugar reduces?
Tallins test (Ag0
Fehling’s Test (Cu)
Benedict’s Solution (Cu)
How to tell whether boat or chair is most stable?
Confirmation with most OH groups axial
Alpha =
fish
beta =
boat
