Unit 2 Enzymology Flashcards
(140 cards)
1
Q
What is measured in enzyme activity?
A
Increase in product formation, decrease in substrate concentration, decrease in coenzyme concentration, increase in altered coenzyme concentration
2
Q
Why is enzyme activity measured at zero-order kinetics?
A
Because the reaction is dependent on enzyme concentration and not substrate concentration
3
Q
What are the two methods of measuring enzyme activity?
A
Fixed-time (endpoint measurement) and Continuous monitoring (kinetic assay)
4
Q
What is the International Unit (IU) of enzyme activity?
A
The amount of enzyme that catalyzes the reaction of 1 μmol of substrate per minute under specified conditions
5
Q
Which enzymes are used as reagents in diagnostic tests?
A
Glucose oxidase, hexokinase, cholesterol esterase, cholesterol oxidase, uricase, lipase
6
Q
What are the major enzyme classifications?
A
Transferases, Hydrolases, Oxidoreductases, Lyases, Isomerases, Ligases
7
Q
Which creatine kinase (CK) isoenzyme is associated with the brain?
A
CK-BB (CK-1)
8
Q
Which CK isoenzyme is most abundant in skeletal muscle?
A
CK-MM (CK-3)
9
Q
What is the significance of CK-MB elevation?
A
It indicates myocardial infarction (heart attack)
10
Q
Which CK isoenzyme moves the fastest in electrophoresis?
A
CK-BB
11
Q
What is the normal reference range of total CK for males?
A
46-171 U/L
12
Q
Which enzyme is a late marker for myocardial infarction?
A
Lactate dehydrogenase (LD)
13
Q
What is the most abundant LD isoenzyme in normal serum?
A
LD-2
14
Q
What is an LD flipped pattern and what does it indicate?
A
LD-1 > LD-2; indicates myocardial infarction
15
Q
Which LD isoenzymes are elevated in liver disease?
A
LD-4 and LD-5
16
Q
What are the two methods for measuring LD activity?
A
Wacker (forward) and Wroblewski-La Due (reverse)
17
Q
Which enzyme is more specific for liver disease, AST or ALT?
A
ALT (Alanine aminotransferase)
18
Q
What is the optimal pH for AST measurement?
A
7.3-7.8
19
Q
What enzyme is the earliest to rise in myocardial infarction?
A
CK-MB
20
Q
What enzyme is associated with alcohol-induced liver disease?
A
Gamma-glutamyl transferase (GGT)
21
Q
Which enzyme is more specific for hepatobiliary disease, ALP or GGT?
A
GGT
22
Q
What is the most heat-stable ALP isoenzyme?
A
Placental ALP
23
Q
What method is used to differentiate ALP isoenzymes?
A
Electrophoresis and heat stability tests
24
Q
What enzyme is elevated in Paget’s disease?
A
Alkaline phosphatase (ALP)
25
Which ALP isoenzyme is most sensitive to heat denaturation?
Bone ALP
26
What enzyme is used in rape investigations?
Acid phosphatase (ACP)
27
Which isoenzyme of ACP is inhibited by tartrate?
Prostatic ACP
28
What enzyme is the most specific for acute pancreatitis?
Lipase (LPS)
29
What is the diagnostic significance of amylase?
Elevated in acute pancreatitis and mumps
30
Which amylase isoenzyme is found predominantly in urine?
P-type (pancreatic) amylase
31
Which method for measuring amylase involves iodine and starch?
Amyloclastic method
32
What condition shows increased amylase but normal lipase?
Mumps or parotitis
33
What enzyme is involved in glucose metabolism and hemolysis disorders?
Glucose-6-phosphate dehydrogenase (G-6-PD)
34
What is the optimal pH for acid phosphatase activity?
pH 5.0
35
Which enzyme is highly unstable and should be stored at room temperature?
Lactate dehydrogenase (LD)
36
What enzyme increases in chronic alcoholism?
Gamma-glutamyl transferase (GGT)
37
Which method for CK measurement is most preferred?
Oliver Rosalki (reverse reaction)
38
What enzyme is increased in Duchenne muscular dystrophy?
Creatine kinase (CK-MM)
39
What enzyme is involved in the transfer of amino groups?
Aminotransferases (AST and ALT)
40
What enzyme catalyzes the hydrolysis of phosphate esters at an alkaline pH?
Alkaline phosphatase (ALP)
41
Which enzyme is inhibited by fluoride and mercury?
AST
42
What is the preferred specimen for enzyme assays?
Serum (red-top tube)
43
What enzyme is more stable, amylase or lipase?
Lipase
44
Which LD isoenzyme is increased in pulmonary embolism?
LD-3
45
What enzyme shows a peak elevation at 12-24 hours in myocardial infarction?
CK-MB
46
What is the substrate for ALP assays?
p-Nitrophenyl phosphate (pNPP)
47
What is the purpose of adding N-acetyl cysteine in CK assays?
To stabilize CK by preventing oxidation of sulfhydryl groups
48
What enzyme is increased in liver cirrhosis but not in bone disorders?
GGT
49
Which ALP isoenzyme is present in pregnancy?
Placental ALP
50
What enzyme is used in forensic analysis of sexual assault cases?
Acid phosphatase (ACP)
51
Which enzyme is used in myocardial infarction diagnosis besides CK-MB?
Lactate dehydrogenase (LD)
52
What is the preferred method for measuring total CK activity?
Oliver Rosalki (reverse reaction)
53
Which CK isoenzyme is most electropositive?
CK-MM
54
Which CK isoenzyme is most electronegative?
CK-BB
55
What are the tissue sources of CK?
Skeletal muscle, heart, brain
56
Which LD isoenzyme is most abundant in normal serum?
LD-2
57
Which LD isoenzyme is associated with lung and lymphocytes?
LD-3
58
Which enzyme is highly unstable and should be processed within 48 hours?
Lactate dehydrogenase (LD)
59
Which enzyme is measured in rape investigations?
Acid phosphatase (ACP)
60
What is the reference method for CK isoenzyme measurement?
Electrophoresis
61
What is the optimal pH for alkaline phosphatase activity?
9.0-10.0
62
Which enzyme is the best marker for obstructive liver disease?
Gamma-glutamyl transferase (GGT)
63
Which enzyme is most elevated in acute viral hepatitis?
Alanine aminotransferase (ALT)
64
Which enzyme is increased in hemolytic anemia?
Lactate dehydrogenase (LD-1, LD-2)
65
Which enzyme is inhibited by hemolysis due to adenylate kinase?
Creatine kinase (CK)
66
Which enzyme is used in glucose metabolism and is deficient in hemolytic anemia?
Glucose-6-phosphate dehydrogenase (G-6-PD)
67
Which enzyme is the most specific for the pancreas?
Lipase (LPS)
68
Which enzyme is inhibited by tartrate in ACP assays?
Prostatic ACP
69
Which enzyme is a hydrolase that breaks down starch?
Amylase (AMS)
70
Which enzyme is most specific for liver function tests?
Alanine aminotransferase (ALT)
71
What is measured in enzyme activity?
Increase in product formation, decrease in substrate concentration, decrease in coenzyme concentration, increase in altered coenzyme concentration
72
Why is enzyme activity measured at zero-order kinetics?
Because the reaction is dependent on enzyme concentration and not substrate concentration
73
What are the two methods of measuring enzyme activity?
Fixed-time (endpoint measurement) and Continuous monitoring (kinetic assay)
74
What is the International Unit (IU) of enzyme activity?
The amount of enzyme that catalyzes the reaction of 1 μmol of substrate per minute under specified conditions
75
Which enzymes are used as reagents in diagnostic tests?
Glucose oxidase, hexokinase, cholesterol esterase, cholesterol oxidase, uricase, lipase
76
What are the major enzyme classifications?
Transferases, Hydrolases, Oxidoreductases, Lyases, Isomerases, Ligases
77
Which creatine kinase (CK) isoenzyme is associated with the brain?
CK-BB (CK-1)
78
Which CK isoenzyme is most abundant in skeletal muscle?
CK-MM (CK-3)
79
What is the significance of CK-MB elevation?
It indicates myocardial infarction (heart attack)
80
Which CK isoenzyme moves the fastest in electrophoresis?
CK-BB
81
What is the normal reference range of total CK for males?
46-171 U/L
82
Which enzyme is a late marker for myocardial infarction?
Lactate dehydrogenase (LD)
83
What is the most abundant LD isoenzyme in normal serum?
LD-2
84
What is an LD flipped pattern and what does it indicate?
LD-1 > LD-2; indicates myocardial infarction
85
Which LD isoenzymes are elevated in liver disease?
LD-4 and LD-5
86
What are the two methods for measuring LD activity?
Wacker (forward) and Wroblewski-La Due (reverse)
87
Which enzyme is more specific for liver disease, AST or ALT?
ALT (Alanine aminotransferase)
88
What is the optimal pH for AST measurement?
7.3-7.8
89
What enzyme is the earliest to rise in myocardial infarction?
CK-MB
90
What enzyme is associated with alcohol-induced liver disease?
Gamma-glutamyl transferase (GGT)
91
Which enzyme is more specific for hepatobiliary disease, ALP or GGT?
GGT
92
What is the most heat-stable ALP isoenzyme?
Placental ALP
93
What method is used to differentiate ALP isoenzymes?
Electrophoresis and heat stability tests
94
What enzyme is elevated in Paget's disease?
Alkaline phosphatase (ALP)
95
Which ALP isoenzyme is most sensitive to heat denaturation?
Bone ALP
96
What enzyme is used in rape investigations?
Acid phosphatase (ACP)
97
Which isoenzyme of ACP is inhibited by tartrate?
Prostatic ACP
98
What enzyme is the most specific for acute pancreatitis?
Lipase (LPS)
99
What is the diagnostic significance of amylase?
Elevated in acute pancreatitis and mumps
100
Which amylase isoenzyme is found predominantly in urine?
P-type (pancreatic) amylase
101
Which method for measuring amylase involves iodine and starch?
Amyloclastic method
102
What condition shows increased amylase but normal lipase?
Mumps or parotitis
103
What enzyme is involved in glucose metabolism and hemolysis disorders?
Glucose-6-phosphate dehydrogenase (G-6-PD)
104
What is the optimal pH for acid phosphatase activity?
pH 5.0
105
Which enzyme is highly unstable and should be stored at room temperature?
Lactate dehydrogenase (LD)
106
What enzyme increases in chronic alcoholism?
Gamma-glutamyl transferase (GGT)
107
Which method for CK measurement is most preferred?
Oliver Rosalki (reverse reaction)
108
What enzyme is increased in Duchenne muscular dystrophy?
Creatine kinase (CK-MM)
109
What enzyme is involved in the transfer of amino groups?
Aminotransferases (AST and ALT)
110
What enzyme catalyzes the hydrolysis of phosphate esters at an alkaline pH?
Alkaline phosphatase (ALP)
111
Which enzyme is inhibited by fluoride and mercury?
AST
112
What is the preferred specimen for enzyme assays?
Serum (red-top tube)
113
What enzyme is more stable, amylase or lipase?
Lipase
114
Which LD isoenzyme is increased in pulmonary embolism?
LD-3
115
What enzyme shows a peak elevation at 12-24 hours in myocardial infarction?
CK-MB
116
What is the substrate for ALP assays?
p-Nitrophenyl phosphate (pNPP)
117
What is the purpose of adding N-acetyl cysteine in CK assays?
To stabilize CK by preventing oxidation of sulfhydryl groups
118
What enzyme is increased in liver cirrhosis but not in bone disorders?
GGT
119
Which ALP isoenzyme is present in pregnancy?
Placental ALP
120
What enzyme is used in forensic analysis of sexual assault cases?
Acid phosphatase (ACP)
121
Which enzyme is used in myocardial infarction diagnosis besides CK-MB?
Lactate dehydrogenase (LD)
122
What is the preferred method for measuring total CK activity?
Oliver Rosalki (reverse reaction)
123
Which CK isoenzyme is most electropositive?
CK-MM
124
Which CK isoenzyme is most electronegative?
CK-BB
125
What are the tissue sources of CK?
Skeletal muscle, heart, brain
126
Which LD isoenzyme is most abundant in normal serum?
LD-2
127
Which LD isoenzyme is associated with lung and lymphocytes?
LD-3
128
Which enzyme is highly unstable and should be processed within 48 hours?
Lactate dehydrogenase (LD)
129
Which enzyme is measured in rape investigations?
Acid phosphatase (ACP)
130
What is the reference method for CK isoenzyme measurement?
Electrophoresis
131
What is the optimal pH for alkaline phosphatase activity?
9.0-10.0
132
Which enzyme is the best marker for obstructive liver disease?
Gamma-glutamyl transferase (GGT)
133
Which enzyme is most elevated in acute viral hepatitis?
Alanine aminotransferase (ALT)
134
Which enzyme is increased in hemolytic anemia?
Lactate dehydrogenase (LD-1, LD-2)
135
Which enzyme is inhibited by hemolysis due to adenylate kinase?
Creatine kinase (CK)
136
Which enzyme is used in glucose metabolism and is deficient in hemolytic anemia?
Glucose-6-phosphate dehydrogenase (G-6-PD)
137
Which enzyme is the most specific for the pancreas?
Lipase (LPS)
138
Which enzyme is inhibited by tartrate in ACP assays?
Prostatic ACP
139
Which enzyme is a hydrolase that breaks down starch?
Amylase (AMS)
140
Which enzyme is most specific for liver function tests?
Alanine aminotransferase (ALT)
