Enzymes Flashcards
1
Q
What is fermentation
A
Transformation of RAW material such as starch, sugar, etc., into industrial mixtures such as liquors
2
Q
Biotransformation
A
transformation of defined precursors to desired target product (environmental friendly processes to treat waste)
3
Q
Pharmaceutical industry
A
Synthesis and modification of antibiotics
4
Q
product: HF corn syrup
A
Enzyme: Glucose isomerase
5
Q
Product: Lactose-Free Milk
A
Lactase
6
Q
Product: Acrylamide
A
Enzyme: Nitrilase
7
Q
Product: Cocoa butter
A
Enzyme: Lipase
8
Q
Product: Ampicillin
A
Enzyme: Penicillin Amylase
9
Q
Product: L-methionine; L-valine
A
Enzyme: Aminoacylase
10
Q
Product: L-cartidine
A
Enzyme: dehydrate/hydroxylase
11
Q
Product: L-dopa
A
Enzyme: beta-tyrosinate
12
Q
Binding sites are
A
Specific and reversible
13
Q
Reversible binding
A
Equilibrium between the free and bound ligand
14
Q
What are Enzymes
A
Protein catalyst that increase the rate of reaction without being changed in the process
15
Q
Rate
A
Velocity
16
Q
Substrate is
A
Enzyme reactant
17
Q
Recommended names for enzymes (3)
A
Short, most commonly used
Suffix -ase attached to substrate of reaction
OR to description of reaction performed
18
Q
Systematic names of enzymes (3)
A
More complete, complex, used when an enzyme has to be identified without ambiguity
19
Q
Oxidoreductase
A
Catalyze reactions where a molecule is being reduced and one being oxidized (oxidation-reduction reactions)
20
Q
Transferases
A
Transfer Carbon, Nitrogen, Phosphate containing groups
21
Q
Hydrolases
A
Catalyze a hydrolysis cleavage reaction
Adds water
22
Q
Lyases
A
Cleavage of C-C, C-S, C-N bonds
23
Q
Isomerases
A
Rearrangement of bonds within a single molecule
24
Q
Ligases
A
Join together (ligate) two molecules together in an energy dependent process (DNA Ligase joints two DNA molecules) between S,C,N,O
25
Polymerases
Polymerization reactions such as SNA or RNA synthesis
26
Proteases
Break down proteins by hydrolyzing bonds between amino acids
27
Kinases
Addition of phosphate groups to molecules
28
ATPases
Hydrolyzes ATP
29
Synthases
Synthesize molecules in anabolic reaction by condensing two smaller molecules together (ATP SYNTHASE)
30
ACTIVE SITE increases what
Special pocket called the active site which increases specificity
31
ENZYME-SUBSTRATE COMPLEX
Substrates binds to the enzyme, forming the complex ES causing confirmations change in the enzyme that allows a catalysis ... an EP is formed
32
EFFICIENCY (catalyzed vs uncatalyzed)
Reactions catalyzed by enzymes are 10^3-10^8 faster than uncatalyzed reactions
33
SPECIFICITY
Enzymes interact with 1 of few substrates and catalyze only one type of reaction
34
T or F
| Holoenzymes do not need cofactors
False some do need cofactors
35
E+CE= ?
ACTIVE (HOLOENZYMES)
36
E -CF= ?
INACTIVE (APOENZYME)
37
T OR F
ENZYME ACTIVITY CAN BE REGULATED SO THAT THE RATE OF PRODUCTS RESPONDS TO CELLULAR NEEDS
TRUE
IT CAN INCREASE OR DECREASE THE ENZYME ACTIVITY
38
Enzymes are located where?
In specific organelles in cell
39
Compartmentalization
Some reactions are isolated from others avoiding competition for the substrate or enabling more favorable conditions
40
Transition state
After the active site binds to substrate and initiates the conversion to products by transition state.
Stabilizing transition state an enzyme can greatly increase the concentration of reactive intermediate that can be converted to product accelerating the reaction
41
How does an enzyme increase the concentration of an reactive intermediate?
Through transition state which is when the substrate is converted to a product by accelerating the reaction
42
Enzymology
Measurement of the appearance of products as a function of time
43
Leonor Michaelis-Maud equation (ENZYME VS SUBSTRATE CONCENTRATION)
Concentration of substrate is GREATER than the concentration of enzyme
44
Leonor Michaelis-Maud equation describes what
describes how the velocity of reaction varies with the substrate concentration
45
Leonor Michaelis-Maud equation TIME
Enzymatic reactions show a steady-state, ES complex does not change with time
The rate of formation of ES is equal to the rate of breakdown
46
Leonor Michaelis-Maud equation VELOCITY
Initial velocity of reaction is used to analyze enzymatic reactions
Vo= (Vmax [S])/ (Km + [S])
47
Initial velocity Michaelis
Vo= (Vmax [S])/ (Km + [S])
48
Michaelis constant equation
Km= (k1+k2)/ k1
Reflects the affinity of the enzyme for substrate
49
T OR F
| Km is equal to the substrate concentration at which the reaction velocity is half
TRUE
| Km= [S] THEN Vmax/2
50
T OR F
Km varies with the enzyme concentration
FALSE
IS WITH THE SUBSTRATE CONCENTRATION
51
ENZYME CONCENTRATION (MICHAELIS)
the rate of the reaction is DIRECTLY PROPORTIONAL to the enzyme concentration
52
Order of reaction: 1st order
If [S] is LOWER than Km then the velocity of reaction is Nearly proportional to the concentration of substrate
53
Order Zero
at high substrate concentration, VELOCITY of reaction is CONSTANT and EQUAL to Vmax
Rate of reaction is independent of substrate concentration
54
T OR F
The plot of initial reactions velocity against substrate concentration is hyperbolic
TRUE
55
T OR F
Allosteric enzymes show a sigmoidal curve
True, they do not show a Michaels kinetics
56
Lineweaver-Burke plot
1/Vo= (Km/ Vmax[S]) + 1/Vmax
57
Factors that affect reaction velocity
Substrate concentration
Temperature
pH
Inhibitors
58
How does [S] affect velocity of reaction
The rate of an enzyme/catalyzed reaction increases with the substrate concentration until a maximal velocity is reached... SATURATION
59
TEMPERATURE vs velocity
Velocity increases with temperature until a peak is reached.
Further elevation of temperature will result in decrease of velocity ... DENATURATION
60
DENATURATION IS?
when the temperature elevation is too high that it causes the velocity of the reaction to decrease
61
The optical temp for most mammalian enzymes is
35-40 C
62
pH and velocity (3)
Extreme pH conditions can affect reaction velocity
It affects the ionization state of active site
Denatured enzymes
63
Inhibitors
Any substance that can diminish the velocity of an enzyme catalyzed reaction
64
Reversible inhibitors
Bind to enzyme through NON COVALENT bonds
65
Competitive inhibitors
Binds to the same site of substrate competing with it
66
T OR F
CONPETITIVE INHIBITORS REDUCE AFFINITY, DECREASE Km, Vmax is changed
FALSE
REDUCE AFFINITY, INCREASE KM AMD VMAX IS UNCHANGED
67
SATING DRUGS ARE AN EXAMPLE OF WHAT TYPE OF INHIBITOR?
COMPETITIVE, IT OCCUPIES THE ACTIVE SITE OF E HYDROXYMETHYLGLUTANYL COA REDUCTASE
68
The 1st step of cholesterol synthesis is inhibited by ?
Competitive inhibitor
69
Non competitive inhibitor
Binds at a different site than the substrate can also bind to free enzymes
70
T OR F
NON COMPETITIVE INHIBITORS INCREASE VMAX AND CHANGE KM
FALSE IT DECRESES VMAX AND KM IS UNCHANGED
71
Catalytic activity of enzymes depend on small molecules called
COFACTORS
72
Cofactors are
Non protein molecule that work as helpers for the enzyme
73
COENZYMES
Small organic molecules derived from vitamins and can be tightly or loosely bound to enzyme
74
When coenzymes are tightly bound they're called
Prosthetic groups
75
Loosely bound coenzymes are
Co-substrates because they bind to and are released from enzymes like substrates
76
Inactive precursors are activated how
Activated by cleavage of one of the few peptide bonds
77
Zymogens
Inactive precursors
78
T OR F
PROTEOLYTIC ACTIVATION NEEDS ATP
FALSE
79
What is the zymogens and active site of the synthesis in stomach
Pepsinogen, pepsin
80
What is the zymogens and active site of the synthesis in pancreas (cc, tt, pc, pe)
Chymotrypsogen- chymotrypsin
Trypsinogen- trypsin
Procarboxypeptidase- carboxypeptidase
Protealatase- elatase
81
Proteolysis: blood clotting is mediated by
A cascade of PROTEOLYTIC activations that ensure a rapid and amplified response to trauma
82
Fibrous protein collagen
Major constituent of skin and bone, derived from procollagen a soluble precursor
83
Example Developmental processes in proteolysis
Metamorphosis
84
Apoptosis
Programmed cell death
85
Enzyme activity regulation
Mechanisms for regulating enzyme activities, effector, results noted in enzyme action and time required to see the effect
86
Allosteric activation
Active site becomes AVAILABLE to the substrate when regulatory molecules bind to a DIFFERENT site on enzyme
87
Allosteric deactivation
Active site becomes INACTIVE to the substrate when regulatory molecules binds to different site on enzyme
88
What happens when modifiers bind to the enzyme in a different site than the substrate
It changes the affinity of the enzyme substrate reaction or modifies the maximal catalytic activity of the enzyme
89
Homotropic effectors
When substrate serves as an effector
90
Heterotopic effector
Effector is different from substrate
91
T OR F
| FEEDBACK INHIBITION IS AM EXAMPLE OR HOMOTROPOC EFFECTORS
FALSE IS AN EXAMPLE OF HETEROTOPIC EFFECTORS
92
Covalent modificators
Addition or removal of a phosphate group from a specific amino acid on the enzyme (ser, thru, tyr)
93
T OR F
| CELLS CANNOT REGULATE THE AMOUNT OF ENZYME ALTERING THE RATE OF ENZYME DEGRADATION OR THE RATE OF SYNTHESIS
FALSE
THEY CAN
INCREASE= KNDUCTION
DECREASE=Repression
94
How can we use enzymes in clinical diagnosis
Through blood tests.
95
High plasma levels means
Damage
