Chapter 19- Enzymes Flashcards
1
Q
Proteins that catalyze biochemical reactions
A
Enzymes
2
Q
Enzymes that catalyze oxidation-reeducation (redox)reactions
A
Oxidoreductase
3
Q
An oxidoreductase enzyme that removes hydrogen from a molecule of lactate
A
Lactate dehydrogenase
4
Q
T or F:other subclasses of the oxidoreductases include oxidases and reductases
A
T
5
Q
Enzymes that catalyze the transfer of functional groups from one molecule to another
A
Transferases
6
Q
An enzyme that catalyzes the transfer of an amino functional group
A
Transaminase
7
Q
And enzyme that catalyzes the transfer of a methyl group
A
Transmethylase
8
Q
An enzyme that catalyzes the transfer of a phosphorylation group
A
Kinase
9
Q
What do kinases play a major role in
A
Energy harvesting processes involving ATP
10
Q
An enzyme that catalyzes the transfer of a phosphorylation group from adenosine triphosphate (ATP) to a molecule of glucose in the first reaction of glycolysis
A
Hexokinase
11
Q
An enzyme class that function through the addition of a water molecule to a bond, resulting in a bond breakage
A
Hydrolases
12
Q
Class of enzymes important to the digestive system
A
Hydrolases
13
Q
Catalyze the hydrolysis of glycosidic bonds between monosaccharides in a polysaccharide
A
Alpha- amylase
14
Q
Catalyze the hydrolysis of peptide bonds in proteins to release amino acids
A
Proteases
15
Q
Catalyze the hydrolysis of the ester bonds in triglycerides
A
Lipases
16
Q
Class of enzymes that Catalyze the addition of a group to a double bond or the removal of a group to form a double bond
A
Lyases
17
Q
Fumarase if an example of what class of enzymes
A
Lyases
18
Q
What role does fumarase play in the citric acid cycle?
A
Catalyze the addition of a water molecule to the double bond of the substrate fumurate
19
Q
What is the product that forms when fumarase catalyzes the addition of a water molecule to the double bond of the substrate fumurate?
A
Malate
20
Q
Catalyzes the removal of an acetyl group from a molecule of citrate to form a double bond
A
Citrate lyase
21
Q
What does ~ represent?
A
A high energy bond
22
Q
What enzyme class is important in glycolysis
A
Isomerases
23
Q
What enzyme group rearranges functional groups within a molecule and catalyze the conversion of one isomer into another
A
Isomerases
24
Q
Converts one structural isomer, 3-phosphoglycerate, into another, 2-phosophoglycerate
A
Phosphoglycerate mutase
25
Phosphoglycreate mutase is in what class of enzymes
Isomerases
26
Class of enzymes that catalyze a reaction in which a C—C, C—S, C—O, or C—N bond is made or broken
Ligases
27
Catalyzes the joining of the hydroxyl group of a nucleotide in a DNA strand with the phosphorylation group of the adjacent nucleotide to form a phosphoester bond
DNA ligase
28
Common names for some enzymes are derived from the name of the ________
Substrate
29
The reactant that binds to the enzyme and is converted into product
Substrate
30
Molecules required by some enzymes to serve as donors or acceptors of electrons, hydrogen atoms, or other functional groups during a chemical reaction
Coenzymes
31
Transglutaminase is also known as
Meat glue
32
Belongs to a family of enzymes that catalyze a reaction between a glutamine residue in a protein and a lysine residue in the same or another protein
Transglutaminase
33
Factor _____ is essential for the formation of blood clots and is a Transglutaminase
XIII
34
How do you medically treat someone with Factor XIII deficiency
Give Transglutaminase
35
How does an enzyme speed up a chemical reaction?
Changes the path by which the reaction occurs, providing a lower energy route for the conversion of the substrate into the product—> AKA it lowers the activation energy
36
A reflection of the difference in energy between reactants and products
The Equillibrium constant equation
37
Why can an enzyme NOT alter the equilibrium constant for the reaction that is catalyzes?
The difference in energy between the reactants and the products is always the same
38
The threshold energy that must be overcome to produce a chemical reaction
Activation energy
39
T or F: as long as the substrate concentration increases , there is a direct decrease in the rate of the reaction
False… its a direct INCREASE in the rate of the reaction
40
T or F: the reaction rate of a reaction if independent of the amount of enzyme that is available
F: it is dependent on the amount of enzyme available
41
The part of the enzyme that binds with the substrate
The active site
42
With what forces does an enzyme attract and hold its substrate
Weak, noncovalent interactions—> hydrogen bonding, van der walls, dipole-dipole, electrostatic attractions
43
Who proposed the enzyme fit model we use today
‘Daniel E. Koshland
44
Model of enzyme activity that proposes that and active site of the enzyme is a flexible pocket that approximates and then molds to substrate shape (rather than it being a rigid model)
Induced fit model
45
The ability of the enzyme to bind to only one , or a very few, substrates
Enzyme specificity
46
The four classes of enzyme specificity
1. Absolute specificity
2. Group specificity
3. Linkage specificity
4. Stereochemical specificity
47
Type of enzyme specificity that catalyzes the reaction of only one substrate
Absolute specificity
48
Aminoacyl tRNA synthetases exhibit what type of specificity
Absolute
49
Type of specificity where an enzyme that catalyzes reactions involving similar molecules containing the same functional group
Group specificity
50
What type of specificity does hexokinase have
Group specificity
51
Type of specificity where an enzyme catalyzes the formation or breakage of only certain bonds in a molecule
Linkage specificity
52
Proteases, such as trypsin, chymotrypsin, and elastase are examples of what type of enzyme specificity
Linkage
53
Why are Proteases, such as trypsin, chymotrypsin, and elastases examples of linkage specificity
Selectively hydrolyze peptide bonds
54
An enzyme specificity that can distinguish one enantiomer from the other
Stereo chemical specificity
55
What type of specificity do most enzymes of the body exhibit
Stereochemical
56
State in which the substrate is in an intermediate form, having features of both the substrate and the product
Transition state
57
The _______state of an enzyme favors conversion of the substrate into product and release of the product
Transition
58
The first protease inhibitor to be prescribed for pediatric AIDS patients
Nelfinavir
59
Most recent HIV medication that is recommended for adults and adolescents
Darunavir
60
In enzymes that require a non protein prosthetic group, the protein portion is called ___________ and the non protein group is called __________
Apoenzyme and cofactor
61
The apoenzyme and cofactor together form the active enzyme called:
Holoenzyme
62
Organic molecules that serve as carriers of electrons or chemical groups
Coenzymes
63
True or false: coenzymes can only donate groups to the substrate, they cannot accept groups that are removed from the substrate
False: they can both donate and accept
64
An organic substance that is required in the diet in small amounts
Vitamins
65
The only water soluble vitamins acclimated with a coenzyme
Vitamin C
66
NAD + and NADP+ are derived from what vitamin
Niacin
67
FAD is made from what vitamin
Riboflavin
68
Cytoplasm of the cell has a pH of
7.0
69
The pH at which an enzyme functions optimally
PH optimum
70
True or false: making a more basic or more acidic sharply decreases the rate of the reaction
True
71
Why does a increase or decrease in pH decrease the rate of a reaction?
Alters the degree of ionization of amino acid R groups in the protein, as well as the extend to which they can hydrogen bond—> enzyme is denatured
72
Optimum pH of pepsin
2.0
73
A proteolytic enzyme in digestion that functions well in high pH environment
Trypsin
74
Membrane bound vesicles containing about 50 different kinds of Hydrolases that degrade large biological molecules into small molecules
Lysosomes
75
Optimal pH of lysosomal enzymes
4.8
76
Explain protective mechanism of lysosomal membranes
Function optimally at pH of 4.8 and if they leak out of the lysosome or if a lysosome ruptures, the cytoplasmic pH of 7.0-7.3 renders them inactive
77
Do enzymes in our cells remain stable at temps higher than 37 degrees Celsius or lower than that temp
Stable when lower than 37 degrees C
78
At the ___________, the enzyme is functioning optimally and the rate of the reaction id maximal
Temperature optimum
79
People with a genetic predisposition for familial emphysema have a genetic defect where
The gene that encodes the human plasma protein alpha 1-antitrypsin
80
Allosteric means:
Other forms
81
Why is enzyme activity controlled and regulated by the cell
To conserve energy
82
A type of enzyme regulation that involves enzymes that have more than a single bonding site and they have active sites that can be altered by the binding of small molecules called effector molecules
Allosteric enzymes
83
Effector binding converts the active site to an inactive configuration
Negative allosterism
84
Effector binding converts the active site to an active configuration
Positive Allosterism
85
__________ allosterism is an example of a feedback inhibition
Negative
86
Allosteric enzymes are the basis for __________ of biochemical pathways
Feedback inhibition
87
Feedback inhibition functions similar to a ________
Thermostat
88
An enzyme in the inactive form
Proenzyme
89
converts the proenzyme by __________ to the active form when it has reached the site of activity
Proteolysis
90
Hydrolysis of a protein is called
Proteolysis
91
Example of a proenzyme in digestion
Pepsinogen
92
Another mechanism that the cell can use to turn an enzyme on or off— a process where chemical group is covalently added to or removed from the protein
Protein modification
93
T or F: protein modification has only the capability to activate an enzyme, it cannot inactivate an enzyme
F: can activate and inactivate
94
What is the most common type of protein modification
Phosphorylation or dephosporylation
95
What is responsible for the covalent modification of an enzymes structure
It is catalyzed by other enzymes
96
_________ add phosphorylation groups to a target enzyme, while _________ remove them
Protein kinases; phosphatases
97
Give an example of phosphorylation inactivating an enzyme
Glycogen synthase
98
T or F: in protein modification, an enzyme can be turned on or off in response to environmental or physiological conditions
T
99
Chemicals that bind to enzymes and wither eliminate or drastically reduce their catalytic activity
Enzyme inhibitors
100
What is a medical example of an enzyme inhibitor
Penicillin
101
How are enzyme inhibitors classified
Reversible vs irreversible and competitive vs non competitive
102
Arsenic is what class of enzyme inhibitors
Irreversible inhibitors
103
Class of enzyme inhibitors that bind very tightly, something’s even covalently, to the enzyme
Irreversible inhibitors
104
Give two examples of irreversible inhibitor enzymes
Snake venom and nerve gases
105
What are reversible, competitive enzymes often called
Structural analogs
106
Molecules that resemble the structure and charge distribution of the natural substrate for a particular enzyme
Reversible, competitive enzyme inhibitors
107
Antidote for poisoning by organophosphates
PAM—> pyridine aldoxime methiodide
108
Sulfa drugs are examples of what kind of enzyme inhibitor
Competitive inhibitors
109
A vitamin required for the transfer of methyl groups in biosynthesis of methionine and the nitrogenous bases required to make DNA and RNA
Folic Acid
110
The substrate foe an early step in folic acid synthesis
PABA—> para-aminobenzoic acid
111
Break the peptide bonds that maintain the primary protein structure
Proteolytic enzymes
112
An enzyme that hydrolyzes dietary proteins in the small intestine
Chymotrypsin
113
Does chymotrypsin act on the amino or carbonyl side of a peptide bond
Carbonyl
114
The pancreatic serine proteases trypsin, chymotrypsin, and elastase all hydrolyze what
Peptide bonds
115
Where are trypsin, chymotrypsin, and elastase produced and transported
Produced in pancreas and transported to small intestine
116
Why are trypsin, chymotrypsin, and elastase called serine proteases?
They have amino acid serine in the catalytic region of the active site that is essential for hydrolysis of the peptide bond
117
A pancreatic serine protease that cleaves peptide bonds on the carbonyl side of the aromatic amino acids and large, hydrophobic amino acids such as methionine
Chymotrypsin
118
A pancreatic serine protease that cleaves peptide bonds on the carbonyl side of basic amino acids
Trypsin
119
A pancreatic serine protease that cleaves peptide bonds on the carbonyl side of glycine and alanine
Elastase
120
3 primary tools used to assess cardiac injury
Myoglobin, creatine kinase-MB (CK-MB), and cardiac troponin I
121
Most reliable test *due to it being cardiac specific)for cardiac injury supported by American college of cardiology
Troponin
122
What is the first cardiac bio marker to appear in a cardiac injury and why
Myoglobin, small and diffuses rapidly
123
Myoglobin is rapidly cleared from body by kidneys in about how many hours
16-36 h
124
When do CK-MB levels usually return to normal
48-72 hours
125
Med used in Cardiac procedure to break apart thrombus in coronary vessel and inhibit thrombin
Streptokinase
126
TPA converts the proenzyme, _______, into the active enzyme, __________
Plasminogen, plasmin
127
Elevation in what two enzymes indicate pancreatitis
Amylase and lipase
128
if ALT elevation is > AST elevation, is the issue liver or heart
Liver
129
A genetic disorder resulting in the deficiency of the enzyme glucocerebrosidase—> leads to buildup of glucocerebroside in liver spleen and bone marrow causing excess lipid in these places. Causes severe anemia, thrombocytopenia, and hepatosplenomegaly, and skeletal problems
Gaucher’s disease
130
What is treatment for Gauchers and what does it do
Cerezyme—> hydrolyzes glucocerebroside into glucose and ceramide so products can be metabolized normally
131
What would happen to the rate of an enzyme catalyzed reaction if pH was increased from 7 to 12
Will cause decrease in rate… most enzymes denature at pH of 11 and enzyme activity would cease
132
Why do extremes of pH inactivate enzymes
Can cause an enzyme to become polyanionic or polycationic which could lead to denaturing and loss of enzyme activity . Less drastic changes in ph alter r group active site which destroys enzyme activity
133
Where is pepsin formed
Stomach
134
Where is trypsin formed
Pancreas
135
T or F: the reaction rate is dependent on the amount of substrate that is available
F… dependent on amount of enzyme
