(4) Enzymes Flashcards
1
Q
Enzymes are protein catalysts involved in the regulation of…
A
biochemical reactions in metabolic pathways.
2
Q
Enzymes increase…
A
the rate of reaction without being altered or consumed during a reaction.
3
Q
Enzymes ___ the activation energy of a reaction.
A
Lower.
4
Q
Role of oxidoreductases.
A
Catalyze oxidation-reduction reactions.
5
Q
Role of transferases.
A
Catalyze group transfer of C, N, or P containing groups.
6
Q
Role of hydrolases.
A
Catalyze cleavage bonds by the addition of water.
7
Q
Role of lyases.
A
Catalyze cleavage of C-C, C-S, & certain C-N bonds, lysis generating a double bond.
8
Q
Role of isomerases.
A
Catalyze optical or geometric isomers, rearrangements.
9
Q
Role of ligases.
A
Catalyze the formation of bonds between C, O, S, N; coupled of hydrolysis of high energy phosphates (ATP required).
10
Q
Reference range of AST.
A
5 - 30 U/L.
11
Q
Reference range of ALT.
A
6 - 37 U/L.
12
Q
Reference range of CPK.
A
15 - 160 U/L (slightly lower in females).
13
Q
Reference range of GGT.
A
6 - 45 U/L (slightly lower for females).
14
Q
Reference range of LDH.
A
Forward: 100-225 U/L.
Reverse: 80 - 290 U/L.
15
Q
Reference range of ALP.
A
30 - 90 U/L.
16
Q
Reference range of AMY.
A
95 - 290 U/L.
17
Q
State the enzyme class for each of the following analytes:
AST, ALT, CK, GGT
A
Transferases.
18
Q
State the enzyme class for each of the following analytes:
LDH, G-6-PD
A
Oxidoreductase.
19
Q
State the enzyme class for each of the following analytes:
PChE, AMY, LIP, ALP, ACP
A
Hydrolases
20
Q
State the enzyme class for each of the following analytes:
ALD
A
Lyase.
21
Q
State the optimal pH for the following analyte:
Amylase
A
6.9 - 7.0
22
Q
State the optimal pH for the following analyte:
ALP
A
10
23
Q
State the optimal pH for the following analyte:
ACP
A
5.0
24
Q
State the optimal pH for the following analyte:
Lipase
A
8.6 - 9.0
25
State the cofactors required for the following analyte:
## Footnote
**CPK**
Mg2+
26
State the cofactors required for the following analyte:
## Footnote
**Lipase**
Colipase
27
State the cofactors required for the following analyte:
## Footnote
**Amylase**
Calcium and Chloride
28
State the cofactors required for the following analyte:
## Footnote
**ALP**
Mg2+, CO2+, Mn2+
29
State the cofactors required for the following analyte:
## Footnote
**LD**
NAD+
30
Explain Kinetic measurement.
Measures the concentration continuously throughout the reaction.
31
Explain End point measurement.
Measures enzyme concentration by measuring a substance after the reaction is stopped (fixed time method).
32
Define the international unit and how it applies to enzymes.
Enzyme activity rather than concentration is measured in serum or plasma. A unit of activity is expressed as IU which is a standard unit established for all methods.
33
In enzyme testing, 1 IU is that quantity of enzyme that will…
catalyze the reaction of one micromole of substance per minute under optimum reaction conditions.
34
Explain zero order kinetics.
The reaction is independent of substrate concentration.
35
Explain first-order kinetics.
Reaction velocity is directly proportional to substrate concentration.
36
Explain competitive inhibition.
Inhibitor similar to the normal substrate molecule competes with the substrate for binding at the activation site.
KM **increases**, Vmax **no change**
37
Explain noncompetitive inhibition.
Inhibitor binds to enzyme at a site other than the active site.
KM **no change**, Vmax **decreases**
38
Explain uncompetitive inhibition.
Inhibitor binds to the ES complex and prevents product formation
KM **decreases**, Vmax **decreases**
39
List the main tissue source for the following enzyme:
## Footnote
**AST**
Liver, myocardial, skeletal muscle, kidney.
40
List the main tissue source for the following enzyme:
## Footnote
**ALT**
Liver, skeletal muscle, kidney, heart, pancreas, lungs, spleen erythrocytes.
41
List the main tissue source for the following enzyme:
## Footnote
**CPK**
Skeletal muscle, brain, stomach muscles.
42
List the main tissue source for the following enzyme:
## Footnote
**GGT**
Kidney, liver, pancreas, and intestine.
43
List the main tissue source for the following enzyme:
## Footnote
**LDH**
Brain, erythrocytes, WBC, kidneys, liver.
44
List the main tissue source for the following enzyme:
## Footnote
**Lipase**
Pancreas (only one of clinical significance), intestinal mucosa, leukocytes, and adipose tissue.
45
List the main tissue source for the following enzyme:
## Footnote
**Amylase**
Salivary glands and acinar cells of pancreas.
46
List the main tissue source for the following enzyme:
## Footnote
**ACP**
Greatest concentration in prostate, liver, kidneys, erythrocytes, platelets, bone.
47
List the main tissue source for the following enzyme:
## Footnote
**ALP**
Liver, bone, placenta, intestine, spleen, and kidneys.
48
State the most prominent location(s) for the following LDH isoenzyme:
## Footnote
**LD1 (HHHH)**
Heart, RBCs.
49
State the most prominent location(s) for the following LDH isoenzyme:
## Footnote
**LD2 (HHHM)**
Renal cortex.
50
State the most prominent location(s) for the following LDH isoenzyme:
## Footnote
**LD3 (HHMM)**
Lung, spleen, pancreas, lymphocytes.
51
State the most prominent location(s) for the following LDH isoenzyme:
## Footnote
**LD4 (HMMM)**
Liver, skeletal muscle.
52
State the most prominent location(s) for the following LDH isoenzyme:
## Footnote
**LD5 (MMMM)**
Liver, skeletal muscle.
53
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**CK**
* MI,
* muscle disorders,
* cerebrovascular accidents,
* CO poisoning,
* after shock or circulatory failure.
54
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**LD**
* Pernicious anemia,
* MI,
* pulmonary disorders,
* hepatitis,
* skeletal disorders.
55
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**AST**
* MI,
* liver disease,
* muscular dystrophy.
56
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**ALT**
* Hepatic disorders,
* Increased ALT specific for liver disease,
* viral hepatitis.
57
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**ALP**
* Hepatobiliary disorders (obstruction)
* Bone diseases
* Pregnancy
* Carcinomas
58
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**ACP**
* Prostate cancer
* Bone disease
* Thrombocytopenia
59
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**GGT**
* Alcoholism
* Hepatobiliary Disorders
60
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**AMS**
* Acute pancreatitis
* Mumps
* Perforated ulcer
* Acute appendicitis
* Macroamylasemia
* AIDS
61
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**LPS**
* Pancreatitis
* Ulcers
* Intestinal obstruction
62
What are the possible disease states for the following serum enzyme elevations:
## Footnote
**5'-nucleatidase**
* Hepatobiliary
63
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Metastatic Carcinoma of Prostate**
**Increased**: acid phosphatase
64
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Myocardial Infarction**
**Increased**: CK, CK-MB, LD, AST
65
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Hepatocelular Disease**
**Increased**: ALP, GGT, AST, ALT, 5'-nucleotidase
66
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Pancreatic Disease**
**Increased**: lipase, amylase
67
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Bone Disease**
**Increased**: ALP, ACP
68
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Muscle Disease**
**Increased**: CK, aldolase, AST, LD
69
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Malignancy**
**Increased**: LD (moderate leukemia, hemolysis), GGT
70
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Alcoholism**
**Increased**: GGT (occult alcohol intake)
71
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Obstructive Jaundice**
**Increased**: GGT, ALP
72
Relate pathologic conditions with an enzyme increase and the degree of elevation:
## Footnote
**Hepatitis, acute and chronic**
**Increased**: AST and ALT, 100x higher elevations in acute vs. chronic
73
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Normal Serum**
**CKMM**: 100%
74
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Skeletal Muscle**
**CKMM**: 100%
75
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Heart**
* *CKMB**: 40%
* *CKMM**: 60%
76
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Brain**
* *CKBB**: 90%
* *CKMM**: 10%
77
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Lung**
* *CKBB**: 90%
* *CKMM**: 10%
78
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Bladder**
* *CKBB**: 95%
* *CKMM**: 5%
79
Indicate the percentage of the distribution of CK isoenzyme in the following human tissues:
## Footnote
**Bowel**
**CKBB**: 100%
80
During a myocardial injury determine the when elevation is apparent, when they peak, and how long it takes for these analytes to return to normal:
## Footnote
**CK**
* *Time of Elevation**: 4 - 8 hours
* *Peak**: 12 - 24 hours
* *Return to Normal**: 3 - 4 days
81
During a myocardial injury determine the when elevation is apparent, when they peak, and how long it takes for these analytes to return to normal:
## Footnote
**LD**
* *Time of Elevation**: 12 - 24 hours
* *Peak**: 48 - 72 hours
* *Return to Normal**: 5 - 10 days
82
During a myocardial injury determine the when elevation is apparent, when they peak, and how long it takes for these analytes to return to normal:
## Footnote
**AST**
* *Time of Elevation**: 6 - 8hrs
* *Peak** 24hrs
* *Return to Normal**: 3 - 5 days
83
During a myocardial injury determine the when elevation is apparent, when they peak, and how long it takes for these analytes to return to normal:
## Footnote
**Troponin (I)**
* *Time of Elevation**: 2 - 6hrs
* *Peak**: 13 - 30hrs
* *Return to Normal**: 7 days
84
During a myocardial injury determine the when elevation is apparent, when they peak, and how long it takes for these analytes to return to normal:
## Footnote
**Myoglobin**
* *Time of Elevation**: 2 - 5hrs
* *Peak**: 2hrs
* *Return to Normal**: 24hrs
85
Which cardiac marker is first to show elevation following a myocardial injury?
Myglobin.
86
What is the significance of the CK relative index (CKI)?
The CKI is an expression of the percentage of the total CK that is attributed to CKMB.
87
Normal reference range of CKI.
0 - 4%
88
CKI values greater than 4% are indicative of…
CKMB increase due to cardiac muscle (i.e. myocardial infarction).
89
Calculate the CK relative index when the total CK = 735 U/L and the CKMB = 23 ug/L.
CKI = (CKMB ug/L)/(Total CK) x100
=23/735 x100
= 3.1%
90
(T/F) Increases in CK and CKMB probably not due to myocardial infarction.
True.
91
What is the clinical usefulness of Troponin?
Troponin is a complex protein of three subunits C, T, and I.
When heart damage occurs, they are released into circulation.
92
What are the troponin assays?
* Quantitative monoclonal immunoassay
* Qualitative immunoassay
93
What analyte is replacing troponin and why?
Due to their specificity and sensitivity, they are being replaced by the use of CK-MB.
94
What are lipases?
Enzymes that hydrolyze the ester linkage of fats to produce alcohols & fatty acids.
95
Why test for lipase levels?
Since acinar cells of the pancreas produce it predominantly, it is useful in diagnosing acute pancreatitis.
96
How does EDTA affect lipase values?
Decreases activity of lipase, causing falsely decreased results.
97
Relate lipase and amylase results in acute pancreatitis and acute appendicitis.
**Acute Pancreatitis**: increased lipase and amylase; hyperlipidemia may suppress lipase resulting in a false normal amount.
Opiates and morphine administered for pain before drawing sample will give a false elevation.
**Acute Appendicitis**: increased amylase, usually normal lipase.
98
List the amylase isoenzymes.
* *P-AMS (Pancreatic)**: P1, P2, and P3
* *S-AMS (Salivary)**: S1, S2, S3
99
What would an increased urine amylase suggest?
Acute pancreatitis, peptic ulcer, intestinal obstruction.
100
What would be an increased serum amylase without an increase in urine indicate?
Benign Macroamylasemia
Enzyme bound to an immunoglobulin or other substance resulting in an unexplained persistent increase in serum.
101
What might GGT increase in myocardial infarction?
Occurs when there is hypoxic liver damage from circulatory disturbances.
102
When is elevated ALP seen under normal physiological conditions?
Pregnancy and bone growth due to normal growth or healing fractures.
103
Explain elevated alkaline phosphatase in children and pregnancy.
ALP is increased in children due to the increased osteoblastic activity during bone growth. ALP increases between labor 16th and 20th weeks of pregnancy until labor. (Placental ALP).
104
What fraction of the ALP enzyme is the most heat stable?
Placenta.
105
Assess the effect of insecticide poisoning on cholinesterase level and the most common method for measurement.
Some organophosphorus compounds found in many insecticides decrease pseudocholinesterase (PChE) activity.
Inhibition of PChE is characterized by tremors and paralysis.
Acylthiocholine esters are used as substrates; activity of PChE is determined from the rate of hydrolysis of butyryl or propionyl thiocholine in the presence of a chromogenic disulfide agent.
106
What enzymes will be affected by slight hemolysis?
LD.
107
What enzymes will be affected by moderate hemolysis?
LD, ALP, amylase, ALT, AST, ACP.
108
Does hemolysis interfere with ALT?
Yes.
109
**Determine the products of the following reaction:**
Creatinine + ATP
Creatinine Phosphate + ADP
110
**Determine the products of the following reaction:**
Lactate + NAD+
Pyruvate + NADH + H
111
**Determine the products of the following reaction:**
Aspartate + Alpha Ketoglutarate
Oxaloacetate + Glutamate
112
**Determine the products of the following reaction:**
Alanine + Alpha Ketoglutarate
Pyruvate + Glutamate
113
**Determine the products of the following reaction:**
Phosphomonoester + H2O
Alcohol + Phosphate ion
114
**Determine the products of the following reaction:**
Glutathione + Amino Acid
Glutamyl-peptide + L-cysteinyl glycine
115
**Determine the products of the following reaction:**
Triglyceride + 2 H2O
2-monoglyceride + 2 fatty acid
