Enzymes Flashcards
(96 cards)
1
Q
It is a compound usually a protein, that acts as a
catalyst for a biochemical reaction
A
Enzyme
2
Q
Composed only of protein
A
Simple Enzyme
3
Q
Has a non protein part in addition to a protein part.
A
Conjugated Enzyme
4
Q
Protein of the conjugated enzyme
A
Apoenzyme
5
Q
Non protein part of the conjugated enzyme
A
Cofactor
6
Q
Biochemically active conjugated enzyme produced from an
apoenzyme and a cofactor
A
Holoenzyme
7
Q
Serves as a cofactor in a conjugated enzyme
A
Coenzyme
8
Q
Reactant in an enzyme catalyzed reaction.
A
Substrate
9
Q
Requires a coenzyme that is oxidized or reduced as the
substrate is reduced or oxidized
A
Oxidoreductase
10
Q
Catalyzes the transfer of a functional group from one
molecule to another
A
Transferase
11
Q
Catalyzes the transfer of amino group from one molecule to another
A
Transaminase
12
Q
Catalyzes the transfer of phosphate group from ATP to give ADP and
a phosphorylated product.
A
Kinases
13
Q
Catalyzes the hydrolysis reaction and is the central to the process of digestion
A
Hydrolase
14
Q
Catalyzes the addition of a group to a double bond or the
removal of a group to form a double bond in a manner
that does not involve hydrolysis or oxidation
A
Lyase
15
Q
Catalyzes the isomerisation of a substrate in a reaction
converting it to a molecule isomeric with itself.
A
Isomerase
16
Q
Catalyzes the bonding together of two molecules into
one with the participation of ATP.
A
Ligase
17
Q
Small part of an enzyme’s structure that is actually
involved in catalysis.
A
Active Site
18
Q
The intermediate reaction species that is formed when a
substrate binds to the active site of an enzyme.
A
Enzyme-Substrate Complex
19
Q
Active site in the enzyme has the fixed, rigid
geometrical conformation.
A
Lock-and-Key Model
20
Q
Enzyme’s active site is not rigid and static.
A
Induced-Fit Model
21
Q
Extent to which an enzyme’s activity is restricted to a
specific substrate, a specific group of substrate, a
specific type of chemical bond, or a specific type of
chemical reaction.
A
Enzyme Specificity
22
Q
Catalyze only one reaction
A
Absolute Specificity
23
Q
Act only on molecules that have a specific functional
group, such a hydroxyl, amino or phosphate groups.
A
Group Specificity
24
Q
A caboxylpeptidase is an example of what specificity?
A
Group Specificity
25
A Catalase is an enzyme of what specificity?
Absolute Specificity
26
Act on the particular type of bond, irrespective to the
| rest of the molecular structure.
Linkage Specificity
27
Act on a particular isomer
Stereochemical Specificity
28
Measures the rate at which an enzyme converts
| substrate to products in a biochemical reaction
Enzyme Activity
29
Factors that affect the enzyme activity are:
Temperature
pH
Substrate Concentration
Enzyme Concentration
30
Temperature at which an enzyme exhibits maximum activity
Optimum Temperature
31
the charge on acidic and basic amino acids located at the active site
depends on?
pH
32
What can affect substrate, causing either protonation or
| deprotonation of groups on the substrate.
pH
33
Active in the stomach, functions best at pH 2.0
Pepsin
34
Operates in the small intestines, function best at pH 8.0
Trypsin
35
physiological pH ranges from?
7.0-7.5
36
True or False
Decreased concentration of substrate will obtain the
enzyme activity.
False
37
Number of substrate molecules transformed per minute by
one molecule of enzyme uunder optimum conditions of
temperature, pH and saturation.
Turnover Number
38
True or False
The greater the enzyme concentration, the lesser the
reaction rate.
False
39
A microbial enzyme active at a conditions that would inactivate
human enzymes as well as enzymes present in other types of
higher organisms
Extremozymes
40
Microorganisms that thrives in extreme environments
Extremophile
41
Microorganisms with optimal growth at pH levels of 3.0 or below
Acidophile
42
Microorganisms with optimal growth at pH levels of 9.0 or above
Alkaliphile
43
Microorganisms whose temperature between 80C and 122C are needed to thrive
Hyperthermophile
44
```
Substance that slows or stops the normal catalytic
function of an enzyme by binding to it.
```
Enzyme Inhibitor
45
Molecule that sufficiently resembles an enzyme substrate in
shape and charge distribution that it can compete with the
substrate for occupancy of the enzymes active site
Competitive Enzyme Inhibitor
46
Molecule that decreases enzyme activity by binding to a site
on an enzyme other than the active site. Presence of this causes a change in the structure of the
enzyme sufficient to prevent the catalytic groups at the active
site from properly effecting their catalyzing action.
Non-competitive Enzyme Inhibitor
47
Molecule that inactivates enzyme by forming a strong
covalent bond to an amino acid side chain group at the
enzymes active site.
Do not have structures similar to that of the enzyme’s normal
substrate.
Irreversible Enzyme Inhibitor
48
True or False
A cell that continually produces large amount of
enzyme for which substrate concentration is always
high is wasting energy. The production of the
enzyme needs to be “ turned off”.
False, substrate concentration is always "very low"
49
True of False
A product of an enzyme Catalyzed reaction that is
present in plentiful amounts in a cell is a waste of
energy if the enzyme stopped catalyzing the
reaction that produces the product. The enzyme needs
to be turned off.
False, if the enzyme "continues to catalyze"
50
Substance that bind at the regulatory sites of allosteric
| enzymes.
Regulators
51
The shape of the active site is changed such that it
| can more readily accept substrate.
Positive Allosteric Regulators
52
Changes to the active site are such that substrate is
| less readily accepted.
Negative Allosteric Regulators
53
A process in which activation or inhibition of the first
reaction in a reaction sequence is controlled by a
product of reaction sequence.
Feedback Control
54
Catalyzes the breaking of peptide bonds that maintain the
| primary structure of protein.
Proteolytic Enzymes
55
Inactive precursor of a proteolytic enzyme.
Zymogens
56
Process in which enzyme activity is altered by
covalently modifying the structure of the enzyme
through attachment of a chemical group or removal of
a chemical group from a particular amino acid within
the enzyme structure.
Covalent Modification
57
Process of addition of the phosphate group to the
| enzyme by protein kinases
Phosphorylation
58
Removal of the phosphate group from the enzyme by
| phosphatases
Dephosphorylation
59
is an enzyme with two or more protein chains (quaternary
| structure) and two kinds of binding sites (substrate and regulator).
Allosteric Enzyme
60
an enzyme involved in the breakdown of glycogen to glucose
Glycogen phosphorylase
61
catalyze removal
| of the phosphate groups.
Phosphatases
62
An enzyme that which effect the addition of phosphate groups
Protein kinases
63
is a substance that kills bacteria or inhibits their growth.
Antibiotic
64
An inhibitor that decreases enzyme activity by binding to a site on the enzyme other
than the active site
Reversible noncompetitive inhibitor
65
An inhibitor that inactivates enzymes by forming a strong covalent bond at the enzyme
active site
Irreversible Inhibitor
66
An inhibitor that has a shape and charge distribution similar to that of the enzyme’s
normal substrate
Reversible competitive inhibitor
67
An inhibitor whose effect can be reduced by simply increasing the concentrate of
normal substrate present
Reversible competitive inhibitor
68
A molecule closely resembling the
substrate. Binds to the active site and
temporarily prevents substrates from
occupying it, thus blocking the reaction
Competitive Enzyme Inhibitor
69
```
A molecule that binds to a site on an
enzyme that is not the active site. The
normal substrate still occupies the active
site but the enzyme cannot catalyze the
reaction due to the presence of the
inhibitor.
```
Noncompetitive Enzyme Inhibitor
70
A molecule that forms a covalent bond to
a part of the active site, permanently
preventing substrates from occupying it.
Irreversible Enzyme Inhibitor
71
The active site has a fixed geometric
shape. Only a substrate with a matching
shape can fit into it.
Lock-and-Key Model
72
```
The active site has a flexible shape
that can change to accept a variety of
related substrates. Enzymes vary in
their degree of specificity
for substrates.
```
Induced-Fit Model
73
Such specifi city means an enzyme will catalyze a particular
reaction for only one substrate. This most restrictive of all specifi cities is not
common. Urease is an enzyme with absolute specificity.
Absolute Specificity
74
Such specificity means an enzyme can distinguish between
stereoisomers. Chirality is inherent in an active site, because amino acids are chiral
compounds. L-Amino-acid oxidase will catalyze reactions of L-amino acids but not
of D-amino acids.
Stereochemical Specificity
75
Such specificity involves structurally similar compounds that have
the same functional groups. Carboxypeptidase is group-specifi c; it cleaves amino
acids, one at a time, from the carboxyl end of the peptide chain.
Group Specificity
76
Such specificity involves a particular type of bond, irrespective of
the structural features in the vicinity of the bond. Phosphatases hydrolyze phosphate–
ester bonds in all types of phosphate esters. Linkage specifi city is the most general of
the specifi cities considered.
Linkage Specificity
77
is the intermediate reaction species that is formed when a
| substrate binds to the active site of an enzyme.
Enzyme-substrate complex
78
is the relatively small part of an enzyme’s structure that is actually involved in catalysis.
Active Site
79
introduction of double bond (oxidation)
by formal removal of two H atoms from
substrate, the H being accepted by a
coenzyme
Dehydrogenase
80
transfer of an amino group between
| substrates
Transaminases
81
transfer of a phosphate group between
| substrates
Kinases
82
hydrolysis of ester linkages in lipids
Lipase
83
hydrolysis of amide linkages in
| proteins
Protease
84
hydrolysis of sugar–phosphate ester
| bonds in nucleic acids
Nuclease
85
hydrolysis of glycosidic bonds in
| carbohydrates
Carbohydrase
86
hydrolysis of phosphate–ester bonds
Phosphatase
87
removal of H2O from substrate
Dehydratase
88
removal of CO2 from substrate
Decarboxylase
89
removal of NH3 from substrate
Deaminase
90
addition of H2O to a substrate
Hydratase
91
conversion of D to L isomer, or vice
| versa
Racemase
92
transfer of a functional group from
one position to another in the same
molecule
Mutase
93
formation of new bond between two
| substrates, with participation of ATP
Synthetase
94
formation of new bond between a
substrate and CO2, with participation
of ATP
Carboxylase
95
an enzyme that catalyzes the formation of peptide
| cross links between polysaccharide strands in bacterial cell walls.
Transpeptidase
96
is an organic compound, essential in small amounts for the proper
functioning of the human body, that must be obtained from dietary sources because the
body cannot synthesize it.
Vitamin
