Enzymes Flashcards
(126 cards)
1
Q
functions as biological catalysts and
are neither consumed nor permanently altered during a chemical
reaction
A
Enzymes
2
Q
enzymes appear in the serum in — amounts after cellular
injury or tissue damage
A
increased
3
Q
the higher the enzyme concentration, the — the reaction, why?
A
faster, because more enzyme is present to bind with the substrate
4
Q
the reaction rate steadily — as more substrate is added
A
increases
5
Q
maximal value of concentration of substrate that no longer results in increased rate of reaction
A
saturation kinetics
6
Q
nonprotein compounds that must bind to particular enzymes
before a reaction occur
A
cofactor
7
Q
3 types of cofactors
A
coenzymes, activators, metalloenzymes
8
Q
are inorganic ions which alters the spatial configuration of the enzyme for proper substrate binding
A
activators
9
Q
It physically binds to the active site of an enzyme – both the substrate and inhibitor compete for the same active site of the enzyme.
A
competitive inhibitor
10
Q
inhibition is reversible when the substrate concentration is —- than the concentration of the competitive inhibitor
A
significantly higher
11
Q
The effect of the competitive inhibitor can be counteracted by
A
adding excess substrate to bind the enzyme
12
Q
It has the ability to alter the apparent Michaelis-Menten constant (Km)
A
competitive inhibitor
13
Q
Inhibitor that does not compete with the substrate but look for areas other than the active site
A
Non-competitive inhibitor
14
Q
The inhibitor binds to the enzyme-substrate (ES) complex
A
Uncompetitive inhibitor
15
Q
binding sites aside from the active site
A
allosteric site
16
Q
These are enzymes (polypeptide chains) having the same catalytic reactions but slightly different molecular structures – various forms occur because of differences in the amino acid sequence of enzymes.
A
isoenzymes
17
Q
Isoenzymes may be differentiated based on
A
electrophoretic
mobility and resistance to heat denaturation
18
Q
enzymes are active at what temperatures
A
25°C, 30°C, or 37°C
19
Q
The rate of denaturation increases as the temperature increases, and is usually significant at —
A
40°C to 50°C
20
Q
Causes change in enzyme structure that results in loss of activity; may be caused by elevated temperature, extreme change in pH, and certain chemicals.
A
denaturation
21
Q
means for every 10°C increase in temperature, there will be a two-fold increase in enzyme activity
A
temperature coefficient (Q10)
22
Q
most physiologic reactions occur in the pH range of
A
7 to 8
23
Q
renders enzymes reversibly inactive
A
low temperatures (refrigeration/freezing)
24
Q
ideal temperature for
preservation of enzymes (longer period of time)
A
-20°C
25
the ideal storage temperature for substrates and coenzymes.
2 to 8°C
26
the ideal storage temperature for LDH (LD4 and LD5)
22°C or room temperature
27
It is a copper-carrying protein with an enzymatic activity
Ceruloplasmin
28
It is a marker of Wilson’s disease
Ceruloplasmin
29
decreased ceruloplasmin is a marker for
Wilson's disease
30
It is a marker for hepatobiliary diseases
Ornithine Carbamoyltransferase
31
Its serum concentration may provide a useful marker of disease severity, and thus could be a useful marker for a high risk of hepatitis C occurrence
Ornithine Carbamoyltransferase
32
Ornithine Carbamoyltransferase could be a useful marker for ---
high risk of hepatitis C occurrence
33
It is produced in secretory granules of the pancreatic acinar cell
trypsin
34
It is a major enzyme that serves as an activator of digestive enzymes.
trypsin
35
active form of trypsin
trypsinogen
36
It is only secreted in the pancreas, hence a more specific marker of acute pancreatitis compared to routine amylase test
trypsin
37
Myoglobin elevation
1 - 4 hours
38
Myoglobin peak
6 - 9 hours
39
Myoglobin normalizes
18 - 24 hours
40
Hemolysis decreases or increases enzyme concentration?
increases
41
lactescense or milky specimen decreases or increases enzyme concentration?
descreases
42
Enzyme nomenclature, the first digit is
classifications
43
Enzyme nomenclature, 2nd and 3rd digits represent ---
subclass
44
Enzyme nomenclature, final and fourth number/s is the ---
serial number
45
catalyze an oxidation-reduction reaction between two substrates
oxidoreductase
46
catalyze the transfer of a group other than hydrogen from one substrate to another.
transferases
47
catalyze hydrolysis of various bonds
hydrolases
48
catalyze removal of groups from substrates without hydrolysis; the product contains double bonds
lyases
49
catalyze the interconversion of geometric, optical, or positional isomers.
isomerases
50
catalyze the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in adenosine triphosphate (ATP) or a similar compound.
ligases
51
is water-free cavity, where the substrate interacts with particular charged amino acid residues; is a 3-dimensional protein structure
active site
52
is a cavity other than the active site; may bind regulator molecules
allosteric site
53
When bound tightly to the enzyme, the coenzyme is called a
prosthetic group
54
Apoenzyme (enzyme portion) and coenzyme forms a complete and active system known as
holoenzyme
55
Digestive enzymes in its inactive form originally secreted from the organ of production is called a
proenzyme or zymogen
56
A German scientist who postulated the lock and key model in 1894 to explain the enzyme’s mode of action
Emil Fischer
57
It is based on the premise that the shape of the substrate must fit into the enzyme
Emil Fisher’s / Lock and Key Theory
58
Proposes that the binding of a substrate or some other molecule to an enzyme causes a change in the shape of the enzyme so as to enhance or inhibit its activity.
Kochland's/Induced Fit Theory
59
It is a phosphoric monoester hydrolase; predominantly secreted from the liver
5’ Nucleotidase (5’ NT)
60
It is a marker for hepatobiliary disease and infiltrative lesions of the liver.
5’ Nucleotidase (5’ NT)
61
5’ Nucleotidase (5’ NT) is routinely increased or decreased in cholestatic disorder?
increased
62
substrate of 5’ Nucleotidase (5’ NT)
5’-monophosphate (5’-IMP)
63
It is also known as the butyrylcholinesterase (BuChe) or acetycholine acylhydrolase.
Pseudocholinesterase (PChE)
64
It is secreted by the liver, hence, measurement of this enzyme reflects synthetic function rather than hepatocyte injury; a secondary liver function test.
Pseudocholinesterase (PChE)
65
It is a marker of insecticide/pesticide poisoning and also determines high exposure to nerve poisons such as sarin
Pseudocholinesterase (PChE)
66
Pseudocholinesterase (PChE) is readily available in --- compared to
acetylcholinesterase.
plasma
67
substrate of Pseudocholinesterase (PChE)
Butyrylcholine
68
Angiotensin - Converting Enzyme requires this for activation
zinc
69
It converts the inactive angiotensin I to its active form, the angiotensin II, within the lungs.
Angiotensin - Converting Enzyme
70
It is a diagnostic test for sarcoidosis, and it is a possible indicator of neuronal dysfunction
Angiotensin - Converting Enzyme
71
Main function: To cleave histidine-leucine sequence from a decapeptide called angiotensin I.
Angiotensin - Converting Enzyme
72
It functions to maintain NADPH in the reduced form in the erythrocytes.
Glucose-6-Phosphate Dehydrogenase
73
It is a newborn screening marker
Glucose-6-Phosphate Dehydrogenase
74
Deficiency of this enzyme can lead to drug-induced hemolytic anemia after taking primaquine, an antimalarial drug.
Glucose-6-Phosphate Dehydrogenase
75
Enzymes catalyze physiologic reactions by ---the activation energy level that the substrate must reach for the reaction to occur.
lowering
76
An enzyme combines with only one substrate and catalyzes only one reaction is known as
absolute specificity
77
Enzymes that combine with all the substrates in a chemical group is called
group specificity
78
Enzymes reacting with specific chemical bonds is known as
bond specificity
79
reaction where the reaction rate depends only on enzyme concentration.
zero-order reaction
80
reaction where the reaction rate is directly
proportional to substrate concentration
First-order reaction
81
the reactants are combined; the reaction proceeds for a designated time; the reaction is stopped, and measurement is made
Fixed-time
82
multiple measurements of changed in absorbance are made during the reaction; it is preferred than fixed-time.
Continuous monitoring/kinetic assay
83
represents the relationship between reaction velocity and substrate concentration
Michaelis - Menten Equation
84
Enzymes are quantified based on their absolute values rather than
activity. True or False?
False. Enzymes are quantified based on their activity rather than
absolute values.
85
The units used to report enzyme levels are
activity units
86
enzymes are measured in terms of:
Change in the substrate concentration, product concentration, and coenzyme concentration
87
is the preferred specimen for the measurement of enzymes.
serum
88
is the alternate specimen for enzymes; however, some enzymes (AST and CK) are inhibited.
heparinized plasma
89
Citrate, EDTA, and fluoride plasma specimens may cause --- enzymatic activity.
false decreased
90
It functions to liberate inorganic phosphate from an organic phosphate ester with the concomitant production of an alcohol.
Alkaline Phosphatase (ALP)
91
Alkaline Phosphatase (ALP) is predominantly found in
the cell membranes
92
Alkaline Phosphatase (ALP) reference range
30 – 90 U/L
93
Major isoenzymes of ALP
liver, bone, placental, intestinal
94
The most abundant plasma ALP isoforms are coded by a single gene on chromosome 1, producing what isoenzymes?
liver, bone, and kidney
95
Gene on chromosome 2 code for what ALP isoenzymes?
placental and intestinal ALP
96
In healthy sera, ALP levels are derived from
liver and bone
97
During period of growth and muscle development, serum ALP and creatine levels decrease or increase?
increase
98
In normal pregnancy, increased ALP activity can be detected between ---- weeks of pregnancy.
16 and 20 weeks
99
In blood groups ----, intestinal ALP is increased after consumption of a fatty meal.
O and B
100
Placental ALP is lower in pregnant women of blood groups ---
A and AB
101
When total ALP activity is elevated, mostly it is contributed by
liver isoenzyme
102
It is also known as the MtCK or non-muscle/ubiquitous MtCK (uMtCK)
Intramitochondrial CK
103
It may be reliable independent predictor of development of hepatocellular carcinoma.
Intramitochondrial CK
104
It supports the myofibrillar structure and contractility
Sarcomeric Muscle CK
105
Highest elevation of Creatine Kinase (CK) is seen in what disease
Duchenne’s muscular dystrophy
106
CK isoenzyme increased in cerebrovascular injury
CK-BB
107
CK is a diagnostic test for
neuroleptic malignant syndrome
108
It is an expression of the percentage of the total CK that is attributed to CK-MB
CK Relative Index (CKI)
109
This is computed to know possible release of CK-MB from noncardiac tissues when total CK is very high.
CK Relative Index (CKI)
110
It is a glycolytic enzyme that splits fructose 1,6-diphosphate into two triose phosphate molecules in the metabolism of glucose.
Aldolase (ALDO)
111
It catalyzes the transfer of glutamyl groups between peptides or amino acids through linkage at a gamma-carboxyl group.
Gamma-Glutamyl Transferase (GGT)
112
Gamma-Glutamyl Transferase (GGT) is the most sensitive marker of ---
acute alcoholic hepatitis
113
It is a sensitive indicator of alcoholism (occult alcoholism); however, it is often elevated in alcoholics even without liver disease
Gamma-Glutamyl Transferase (GGT)
114
Regan ALP and Nagao ALP are both inhibited by
phenylalanine
115
ALP is decreased or increased in obstructive jaundice?
increased, due to greater rate of secretion
116
this ALP isoform is used to study low bone mineral disease (BMD) in patients with chronic kidney disease.
B1x
117
defective bone and teeth mineralization
hypophosphatasia
118
this ALP isoenzyme is utilized as a tumor
marker in serum and cerebrospinal fluid (CSF) for most germ cell
tumors
placental alkaline phosphatase (PLAP) or (PALP?)
119
ALP requires this ion for activation
magnesium
120
ALP is inactivated by
EDTA
121
ALPs from most anodal to least anodal
LiBoPlaIn
Liver, Bone, Placenta, Intestine
122
ALPs from most heat stable to most heat labile
Promise, Ikaw Lang Beh
Placental, Intestine, Liver, Bone
123
Reference method; most specific; routine method for ALP
Bowers and Mc Comb (Szasz Modification)
124
--- is a component of ALP, and --- is the enzyme activator.
zinc
magnesium
125
are sources of analytic errors and may cause elevated serum ALP.
hemolysis and diet (fatty meals)
126
decreased or increased ALP is seen in zinc deficiency?
decreased
