(M) Enzymes Flashcards
1
Q
Largely ‘protein’ in nature produced by living cells
A
Enzymes
2
Q
Specific biological proteins involved in the catalysis of biochemical reactions.
A
yaurrr Enzymes
3
Q
TOF. Enzymes alter the equilibrium point, resulting in the formation of products
A
F
4
Q
Plays an important role in Metabolism, Diagnosis, and Therapeutics
A
Enzymes
5
Q
What does an increase of serum or plasma enzyme indicate?
A
Bacterial infection
6
Q
TOF. Inhibition of some enzyme also have therapeutic values
A
Tru
7
Q
Group of enzymes catalyze an oxidation rxn between two substrates?
A
Oxidoreductases
8
Q
Catalyze the transfer of a group other than Hydrogen fr one substrate to another
A
Transferases
9
Q
Catalyzes the hydrolysis of a different bond
A
Hydrolases
10
Q
Catalyzes the removal of groups from a substrate without hydrolysis (*prod. formed contains double bonds)
A
Lyases
11
Q
Catalyze the interconversion of geometric optical/ positional isomers
A
Isomerases
12
Q
Catalyze the joining of two substrate molecules
A
Ligases
13
Q
Enzymes are classified into how many functional classes (EC number classification) ?
A
6
14
Q
Types of Reactions that EC.1 enzymes catalyze
A
Oxidoreductases
15
Q
Types of Reactions that EC.2 enzymes catalyze
A
Transferases
16
Q
Types of Reactions that EC.3 enzymes catalyze
A
Hydrolases
17
Q
Types of Reactions that EC.4 enzymes catalyze
A
Lyases
18
Q
Types of Reactions that EC.5 enzymes catalyze
A
Isomerases
19
Q
Types of Reactions that EC.6 enzymes catalyze
A
Ligases
20
Q
According to the IUB, the 1st no. in the nomenclature of enzymes indicates what?
A
Class
21
Q
According to the IUB, the 2nd no. in the nomenclature of enzymes indicates what?
A
Sub-class
22
Q
According to the IUB, the 3rd no. in the nomenclature of enzymes indicates what?
A
Sub-sub-class
23
Q
According to the IUB, the 4th no. in the nomenclature of enzymes indicates what?
A
Enzyme Serial No.
24
Q
Greatly increase the rate of chemical reactions
A
Enzymes
25
TOF. Without enzymes, there will still be a formation of products
True (but slower)
26
TOF. Enzymes typically disrupt the transformation of one energy form into a more usable form
F (help)
27
TOF. Enzymes require helper molecules
True
28
TOF. Enzymes bind to specific reactants
True
29
Type of enzyme specificity that catalyzes one type of reaction for a single substrate
Absolute
30
Type of enzyme specificity that catalyzes one type of reaction for similar substrates
Group
31
Type of enzyme specificity that catalyzes one type of reaction for a specific type of bond
Linkage
32
TOF. Nearly all enzymes are proteins
True (with le exception of ribozymes)
33
TOF: Enzymes are used up and changed at the end of the reaction
F (not used up and remain unchanged)
34
TOF. Enzymes are free to attach to another substrate after releasing the product
True
35
Difference between the energies of the reactions and the energies of the products of a reaction
Standard free energy change or DG°
36
Energy input required to initiate a reaction
Free Energy of Activation or Activation Energy
37
TOF. Activation Energy for a catalyzed reaction is higher than an uncatalyzed reaction.
False (baliktad sizt)
38
TOF. Spontaneous = Instantaneous
False (spontaneity of a rxn depends on the concentration but it will never be instant)
39
Stable in the air with an unlimited supply of oxygen
Glucose
40
Relationship between Activation Energy and Rate of Reaction
Indirectly proportional
41
The apex of the curve (from activation energy profile) is the energy that drives the
Transition state
42
Enzymes lower the Activation Energy by
Stabilizing the Transition State
43
TOF. The same amount of reactants and products are produced with or w/o enzymes
True (they only differ in the rate of reaction to form the products)
44
The Site that has an important role in stabilizing the Transition State
Google eme,, Active Site
45
Specific Region of the Enzyme that binds to the substate
Active Site
46
Attachment point of substrates in an enzyme
Active Site (Binding Site Cleft)
47
Substrates bind usually thru what interaction?
Noncovalent interaction
48
Components of the Active Site:
1. Contact Residues
2. Catalytic Residues
3. Structural Residues
4. Non-essential Residues
49
Makes up only a small portion of the overall enzyme
Active Site
50
Have complementary structures corresponding to their substrates
Active Site
51
2 Models developed to describe the binding process of substrates
1. Lock and Key Model
2. Induced Fit Model
52
Model that assumes a high-level of similarity between substrate and geometry of the enzyme
Lock and Key Model
53
TOF. In Lock and Key Model the active site has a flexible shape
F (rigid shape)
54
Model; Only substrates with the matching shape can fit
Lock and Key Model
55
Is a key that fits the lock of the active site
Substrate
56
TOF. The lock and key model works for all enzymes
False
57
Binding of the substrate induces a conformation change in the enzyme that result in a complementary fit
Induced-Fit Model
58
Has a greater range of substrate specificity
Induced-Fit Model
59
This model is more consistent with a wider range of enzymes
Induced Fit Model
60
In Induced fit model the active site is
Flexible, not rigid
61
TOF. The shape of the enzyme, active site, and substrate improve catalysis
True
62
In the Michaelis-Menten Approach to Enzyme Kinetics, what does k1 represent?
Rate constant for the formation of the Enzyme-Substrate Complex (ES)
63
In the Michaelis-Menten Approach to Enzyme Kinetics, what does k-1 represent?
Rate constant for the reverse reaction (dissociation of ES)
64
In the Michaelis-Menten Approach to Enzyme Kinetics, what does k2 represent?
Rate constant of ES to form products
65
When was the Michaelis-Menten Equation developed?
late 1913
66
Order of Reaction where the rate depends on concentration of substrate
First order
67
Order of Reaction where the rate does not depend on concentration of substrate
Zeroth order
68
Order of Reaction where the rate depends on concentration of enzyme
First order
69
Amount of enzyme which will catalyze the transformation of 1μmol of substrate per minute
Enzyme unit
70
Catalytic activity which will raise the rate of a reaction by 1 mole per second in a specified system
katal
71
List the ways on how an inhibitor can affect enzymatic reaction
1. Reversible
2. Irreversible
72
Enzyme inhibition where inhibitors permanently bind to the enzyme through the formation of a covalent bond
Irreversible inhibition
73
TOF. In an irreversible inhibition, the enzymes can still be regenerated
False (the inhibitors permanently bind to the active site = not enzymatically active)
74
Inhibitors that easily dissociate
Reversible Inhibition
75
Types of Reversible Inhibition
1. Competitive
2. Uncompetitive
3. Noncompetitve
76
Type of Enzyme Inhibition where the inhibitor resembles the shape of the actual substrate and prevents the substrate from binding to the active site
Competitive
77
Increases Km, Vmax is unaffected
Competitive
78
Can be resolved by increasing the S
Competitive
79
Type of Enzyme Inhibition where an allosteric site is already present before the substrate binds to the active site
Noncompetitive
80
Decreases Vmax, does not affect Km
Noncompetitive
81
Slows down enzyme efficiency (turnover number=how fast the enzyme can catalyze reaction)
Noncompetitive
82
TOF. Catalysis can still occur even in the presence of an inhibitor
False (it does not)
83
The binding of the Substrate (S) to the active site
creates a crevice/pocket called
Allosteric site.
Uncompetitive
84
If it is in close proximity with the ES complex, then this will prevent the S from dissociating from the active site
Uncompetitive
85
Cannot be overcome by increasing S
Uncompetitive
86
Decreases both Km and Vmax=parallel
Uncompetitive
87
Equation that helps in exacting the value for Vmax because it is simply the reciprocal of the constant values in the equation.
Lineweaver Burke Eqn
88
List down the 3 factors that influence enzyme activity
1. Environmental Conditions
2. Cofactors and Coenzymes
3. Enzyme Inhibitors
89
Extreme temperatures are the most dangerous
Environmental Conditions
90
Significant temperature range where denaturation of enzyme occur
40° - 50°
91
TOF. High temperatures may denature (unfold) the enzyme
True
92
TOF. Rate of a chemical reaction
increases with temperature.
True (each 10° inc. in temp will double the rate of reaction until the protein is denatured)
93
The temp at which enzymatic reaction occurs fastest
Optimum Temperature
94
Ideal temperature for an enzymatic reaction
37°
95
TOF. Rate of reaction increases as substrate concentration decreases
False (substrate concentration increases)
96
TOF. Maximum activity occurs when the enzyme is saturated (when all enzymes are binding to the substrate)
True
97
Inorganic substances (zinc, iron, Cu) and vitamins (respectively) are sometimes needed for proper enzymatic activity.
Cofactors and Coenzymes
98
Once coenzymes are bound to enzymes they are called
Prosthetic groups
