Ch. 13 - Enzymes (GGT - G6PD) (RVSP) Flashcards
(114 cards)
0
Q
Serves as the gamma-glutamyl donor in most biologic systems
A
Glutathione
1
Q
Enzyme involved in the transfer of gamma-glutamyl residue from gamma-glutamyl peptides to amino acids, H2O, and other small peptides
A
Gamma-glutamyltransferase (GGT)
2
Q
3 functions of GGT
A
- synthesis of peptides and proteins
- regulation of tissue glutathione levels
- transport of amino acids across cell membranes
3
Q
Tissue sources of GGT
A
Kidney Brain Prostate Pancreas Liver
4
Q
Enzyme used for evaluation of liver and biliary system disorders
A
GGT
5
Q
Enzyme elevated in all hepatobiliary disorders
A
GGT
6
Q
Enzyme increased in patients receiving enzyme-inducing drugs
A
GGT
7
Q
Elevated enzyme in chronic alcoholism
A
GGT
8
Q
Substrate for GGT analysis
A
Gamma-glutamyl-p-nitroanilide
9
Q
Absorbance range in GGT analysis
A
405-420 nm
10
Q
Length of time and temperature that GGT activity is stable
A
1 week at 4°C
11
Q
Reference ranges for GGT
A
M: 6-55 U/L (37°C) (0.1 - 0.9 ukat/L)
F: 5-38 U/L (37°C) (0.1 - 0.6 ukat/L)
12
Q
Class of amylase
A
Hydrolase
13
Q
Enzyme that catalyzes the breakdown of starch and glycogen
A
Amylase (AMY)
14
Q
Enzyme that attacks only alpha, 1-4 glycosidic bonds
A
Alpha-AMY
15
Q
Degradation products produced after alpha-AMY attacks the alpha, 1-4 glycosidic bonds
A
- glucose
- maltose
- dextrins
16
Q
Intermediate chains consisting of alpha, 1-6 branching linkages
A
Dextrins
17
Q
2 components of starch
A
Amylose
Amylopectin
18
Q
Component of starch; long, unbranched chain of glucose molcules, linked by alpha, 1-4 glycosidic bonds
A
Amylose
19
Q
Component of starch; branched-chain polysaccharide with alpha, 1-6 glycosidic linkages at the branch points
A
Amylopectin
20
Q
Important enzyme in the physiologic digestion of starches
A
AMY
21
Q
2 ions needed by AMY for its activation
A
Calcium ion (Ca2+) Chloride ion (Cl-)
22
Q
2 major tissue sources of AMY
A
Acinar cells of the pancreas
Salivary glands
23
Q
Minor tissue sources of AMY
A
Skeletal muscle
Small intestine
Fallopian tubes
Urine
24
Smallest enzyme
AMY
25
Where digestion of starches start
Mouth
26
Enzyme in the mouth that hydrolyzes starches
Salivary AMY
27
Performs the major digestive action of starches once the polysaccharides reach the intestine
Pancreatic AMY
28
Inactivates salivary AMY
Acidity of gastric contents
29
Diagnostic significance of serum and urine AMY
```
Acute pancreatitis
Salivary gland lesions
Intraabdominal diseases
Renal insufficiency
Diabetic ketoacidosis
Hyperamylasemia
```
30
Time when AMY levels begin to rise in acute pancreatitis
5-8 hours after onset of attack
31
Time when AMY levels are at peak in acute pancreatitis
24 hours
32
Time when AMY levels return to normal in acute pancreatitis
3-5 days
33
Condition when the AMY molecule combines with immunoglobulins to form a complex that is too large to be filtered by the glomerulus
Macroamylasemia
34
AMY isoenzyme derived from pancreatic tissue
P-type
35
AMY isoenzyme derived from salivary gland tissue, fallopian tube and lung
S-type
36
AMY isoenzymes that migrate the fastest in electrophoresis
S-type (S1, S2 and S3)
37
AMY isoenzymes that migrate slowly in electrophoresis
P-type (P1, P2 and P3)
38
Most commonly observed AMY isoenzyme fraction in electrophoresis
P2
S1
S2
39
Predominant AMY isoenzyme in acute pancreatitis and renal failure
P3
40
4 methods for AMY assay
- Amyloclastic/Iodometric method
- Saccharogenic method
- Chromolytic/Chromogenic Labelled Substrate method/Colorimetric
- Couple Enzyme Reaction/Continuous-monitoring technique
41
AMY method; measures the disappearance of starch substrate
Amyloclastic
42
AMY method; measures the appearance of the product (reducing sugars)
Saccharogenic
43
AMY method; measures the increasing color from production of product coupled with a chromogenic dye
Chromogenic/Chromolytic/Colorimetric
44
AMY method; coupling of several enzyme systems to monitor amylase activity
Continuous monitoring/Coupled Enzyme reaction
45
Optimal pH for AMY activity
pH 6.9
46
Length of time and temperature where serum and urine AMY is stable
1 week at RT
| 2 months at 4°C
47
Reference ranges for AMY
Serum: 28-100 U/L (37°C) (0.5-1.7 ukat/L)
Urine: 1-15 U/h
48
Enzyme that hydrolyzes the ester linkages of fats to produce alcohols and fatty acids
Lipase (LPS)
49
Substrate requirement for LPS in order for activity to occur
Emulsion
50
Accelerates LPS reactions
Colipase
| Bile salt
51
Major tissue source of LPS
Pancreas
52
Minor tissue sources of LPS
Stomach
| Intestine (small)
53
Diagnostic significance of LPS
Acute pancreatitis
54
Time when serum LPS activity rises after an attack of acute pancreatitis
4-8 hours
55
Time when LPS levels peak in acute pancreatitis
24 hours
56
Time when LPS levels decrease in acute pancreatitis
8-14 days
57
Enzyme that is more specific for pancreatic disorders than AMY measurement
LPS
58
LPS isoenzyme that is the most clinically specific and sensitive
L2
59
Classic method for LPS; used an olive oil substrate
Cherry-Crandall method
60
LPS method; measures the liberated fatty acids by titration after a 24-hour incubation period
Cherry-Crandall method
61
Substrate in Cherry-Crandall method for LPS
Olive oil
62
Substrate now used in Cherry-Crandall method for LPS; more pure form of triglyceride
Triolein
63
LPS method; measures the rate of clearing n a solution for LPS activity
Turbidimetric methods
64
Method for LPS; based on coupled reaction with enzymes such as peroxidase or glycerol kinase
Colorimetric methods
65
Lenth of time and temperature when LPS acitivity is stable
1 week at RT
| 3 weeks at 4°C
66
Reference range for LPS
<0.6 ukat/L)
67
Enzyme class of G-6-PD
Oxidoreductase
68
Tissue sources for G-6-PD
```
Adrenal cortex
Spleen
Thymus
Erythrocytes
Lymph nodes
Lactating mammary gland
```
69
Inheritance pattern of G-6-PD deficiency
Inherited sex-linked trait
70
Maintains NADPH in reduced form
G-6-PD
71
Required to regenerate sulfhydryl-containing proteins (ex. glutathione) In its reduced state
NADPH
72
Protects Hb from oxidizing agents
Glutathione (reduced form)
73
Drug that causes Drug-induced Hemolytic Anemia (DIHA) during G-6-PD deficiency
Antimalarial drugs (Primaquine)
74
Hemolytic anemia caused by antimalarial drugs (Primaquine) in the presence of G-6-PD deficiency
Drug-Induced Hemolytic Anemia (DIHA)
75
Conditions of increased levels of G-6-PD
- MI
| - Megaloblastic anemia
76
Enzyme that does is not elevated during hepatic disorders
G-6-PD
77
Specimen used for suspected G-6-PD enzyme deficiency
Red cell hemolysate
78
Specimen used for suspected G-6-PD enzyme elevation
Serum
79
Reference range for G-6-PD
7.9 - 16.3 U/g Hb (0.1 - 0.3 ukat/g Hb)
80
Diagnostic significance of GGT
- Hepatobiliary disorders
- Enzyme inducing drugs
- Alcoholism (chronic)
- Acute pancreatitis
- Diabetes mellitus
- MI
- Differentiating source of ALP elevation
81
Enzyme-inducing drugs
Warfarin
Phenobarbital
Phenytoin
82
Method of GGT measurement
Sasz Method
83
2 substrates used in Sasz method for GGT
- L-λ-glutamyl-p-nitroanilide (yellow; 405 nm)
| - 5-amino-2-nitrobenzoate (410 nm)
84
Salivary gland lesions related to AMY elevation
Mumps
| Parotitis
85
Intraabdominal disease related to AMY elevations
```
Perforated peptic ulcer
Intestinal obstruction
Cholecystitis
Ruptured ectopic pregnancy
Acute appendicitis
Mesenteric infarction
```
86
Tissue sources of S-type AMY
Salivary gland tissues
Fallopian tubes
Lungs
87
Where does P-type AMY predominate?
Urine
88
Where does S-type AMY predominate?
Serum
89
AMY mtd; measures the disappearance in initial dark blue color of starch-iodine complex
Amyloclastic/Iodometric mtd
90
Reference mtd for AMY
Saccharogenic Mtd
91
Number of mg glucose in 30 mins at 37°C at specific assay conditions
Somogyi units
92
Wavelength for coupled enzyme reaction for AMY
340 nm
93
Substrate for coupled enzyme reaction of AMY
Maltotetrase/maltopentoase
94
Inhibits S-type AMY
Wheat germ lectin
95
Causes falsely normal levels AMY
Plasma triglycerides
96
Inhibits serum AMS activity leading to falsely normal levels in acute pancreatitis with hyperlipemia
Plasma triglycerides
97
Causes falsely increased levels of AMY
Morphine
| Opiates
98
Causes falsely decreased of AMY levels
Oxalates
| Citrates
99
Conversion factor from Somogyi units to IU
1.85
100
Enzyme class of lipase
Hydrolase
101
How many days does LPS elevations persist?
5 days
102
pH for LPS activity
pH 8.6 - 9.0
103
Intraabdominal condition related to LPS elevations
Penetrating duodenal ulcers
Intestinal obstruction
Perforated peptic ulcers
Acute cholecystitis
104
Activators for LPS methods
Albumin/ionized calcium
105
Inhibitors for LPS methods
Heavy metals (ex: quinine)
106
5 methods for LPS activity
```
Turbidimetric Enzyme Reaction
Cherry-Crandall Method (Titrimetric)
Tietz-Borden Mtd
Sigma Tietx
Colorimetric Mtd
```
107
Substrates for Turbidimetric Enzyme reaction for LPS
Olive oil
| Triolein
108
Mtd for LPS; decrease in turbidity is measured as LPS hydrolyzes the turbid substrate fat emulsion
Turbidimetric Enzyme Reaction
109
Mtd for LPS; measures liberated fatty acids released by alkaline titration after 24 hrs incubation
Cherry-Crandall Mtd (Titrimetric)
110
Indicator in Cherry-Crandall Mtd for LPS
Phenolphthalein (salmon color)
111
Indicator used in Sigma Tietx
Thymolphthalein (blue color)
112
Enzymes used in the Colorimetric mtd for LPS
Peroxidase
| Glycerol kinase
113
Causes false decrease in LPS levels
Hemolysis
