PANCREATIC ENZYMES Flashcards
(101 cards)
1
Q
PANCREATIC ENZYMES
These enzymes are:
A
• AMYLASE
• LIPASE
2
Q
The pancreas does not only produce amylase and lipase, it also produces many other enzymes such as,
A
elastase
trypsin
pepsin
3
Q
We ONLY test for AMYLASE and LIPASE to diagnose…
A
ACUTE PANCREATITIS
4
Q
Endocrine = HORMONES from______.
Exits to the_______.
A
Pancreatic Islets
Bloodstream
5
Q
Exocrine = Mainly ENZYMES from_____
Exits through the_____
A
Acinar cells
Pancreatic duct
6
Q
Amylase
EC
A
E.C 3.2.1.1
1,4-D-Glucan Glucanohydrolase
7
Q
AMS
Breakdown of______ to monosaccharides
A
starch and glycogen
8
Q
AMS
Activators:
A
CALCIUM and CHLORIDE
9
Q
Amylase follows the____ specificity; they are bound to react with structures with____
A
LINKAGE
a-1,4-glycosidic bonds.
10
Q
The type of amylase that is present in humans is_____
______is found in plants and microorganisms
A
ALPHA (a)
Beta (B)
11
Q
TISSUE SOURCES OF AMS
A
SALIVARY GLANDS
ACINAR CELLS OF THE PANCREAS
12
Q
Salivary amylase also known as
A
Ptyalin
13
Q
Pancreatic amylase also known as
A
Amylopsin
14
Q
The fact also that the amylase has 2 major sources makes the amylase_____
• If the patient has increased amylase concentration then you can narrow it down to___ organs.
A
NON-SPECIFIC
2
15
Q
MW od Amylase
A
50,000 - 55,000 MW
that why it is easily filtered from the circulation
SMALLEST ENZYME
16
Q
Readily filtered by the glomerulus due to its small molecular weight.
Once inside the glomerulus it is NOT REABSORBED by the tubules.
A
Amylase
17
Q
T or F
We can detect amylase in the urine
A
True
18
Q
- initial digestion of starch by salivary AMS
Inactivated in the stomach. Why?
A
MOUTH
Due to the presence of acid
19
Q
- final digestion by pancreatic AMS
A
SMALL INTESTINE
20
Q
ISOENZYMES OF AMS
A
P-type isoamylase
S-type isoamylase
21
Q
Pancreas
P3: Predominant in AP
A
• P-type isoamylase
22
Q
Salivary gland
Lungs (levels not significant)
Fallopian tubes (levels not significant)
A
S-type isoamylase (None pancreas)
23
Q
____is usually what’s checked when we run a serum sample to check its amylase level content
HIGH____ is indicative of having acute pancreatitis
A
P3
24
Q
DIAGNOSTIC SIGNIFICANCE of Amylase
A
Acute pancreatitis
Salivary gland lesions
Intra-abdominal diseases
25
Acute Pancreatitis (AMS)
• Rise:_____ after the onset of an attack
5-8 Hrs
26
Acute Pancreatitis (AMS)
Peak:
Normalize:
24 Hrs.
3-5 days
27
Salivary Gland Lesions
- disease in parotid glands (Mumps)
Parotitis
28
Acute pancreatitis has 3 possible causes:
1. Duct Obstruction
2. Acinar Cell Iniurv
3. Defective Intracellular Transport
29
Remember that in our pancreas we have proenzymes which acts as a safety net for the pancreas, since proenzymes are inactivated protease, no digestion in itself will happen.
But if the proenzymes are activated WITHIN the pancreas then that would lead to some serious trouble and would cause the pancreas to be digested by its own enzyme.
Acute pancreatitis
30
DUCT OBSTRUCTION
• There is something that OBSTRUCTS the pancreatic duct.
Possible cause of obstruction is…
GALLSTONES AND PARASITES
31
Acute pancreatitis
The obstruction caused by the gallstone causes IMPAIRED BLOOD FLOW.
Thus no oxygen can pass through
No oxygen = NECROSIS
Will also lead to the PREMATURE ACTIVATION of the enzymes.
Duct obstruction
32
Alcohol is also TOXIC to the…
Acinar cells
33
• Can be caused by: Alcohol, Drugs, Trauma, Ischemia and Viruses.
• Which leads to the accidental activation of the enzymes in the pancreas.
ACINAR CELL INJURY
34
• For example trypsinogen. This enzyme should have a different pathway from other enzymes released by the pancreas such as the amylase and lipase.
• If trypsinogen goes to the pathway where amylase and lipase goes then, trypsinogen will be activated into trypsin.
• This is problematic since the trypsinogen was activated within the pancreas itself and will now lead to the digestion of its own cells.
DEFECTIVE INTRACELLULAR TRANSPORT
35
• This is the most common type of Hyperamylasemia
• increased Amylase yet essentially NORMAL
MACROAMYLASEMIA
36
• Persistent increase in serum amvlase is seen without clinical symptoms
Macroamylasemia
37
In these patients, the amylase binds to the______
AMS molecules combine with____
This molecules combined together will now become a big structure
Which cannot be filtered out by the glomerulus.
So it will GO BACK to the blood circulation.
Thus, having increased AMS yet the patient feels normal.
Macroamylasemia
ANTIBODIES or IMMUNOGLOBULINS.
IgG or IgA.
38
ASSAY FOR ENZYME ACTIVITY
AMYLASE
1. Amyloclastic method
2. Saccharogenic method
3. Chromogenic method
4. Continuous monitoring method
39
- measures the appearance of reducing sugars products by the hydrolysis of starch
•classic reference method
Saccharogenic
40
- amylase activity by the following decrease or disappearance or decrease in starch substrate concentration
Amyloclastic
41
•AMS hydrolyzes the starch molecule into smaller units, the iodine is released and a decrease occurs in the initial dark-blue color intensity of the starch-iodine complex.
Amyloclastic method
42
- measures the increasing color from production of product coupled with a dye.
Chromogenic
43
- coupling of several enzyme systems to monitor amylase activity (NADH is produced and measured at 340nm)
Continuous monitoring
44
Measures the disappearance of starch substrate
AMYLOCLASTIC METHOD
45
AMY acts on starch substrate with attached iodine
Hydrolysis releases iodine
Decrease in dark-blue color intensity of starch-iodine complex
Color decrease proportional to AMY concentration
AMYLOCLASTIC METHOD
46
Measures the appearance of the product
SACCHAROGENIC METHOD
47
Starch substrate hydrolyzed to constituent carbohydrates
Reducing sugars measured
Concentration proportional to
AMY activity
SACCHAROGENIC METHOD
48
Saccharogenic method
Classic reference method, reported in…
Somogyi units
49
Starch substrate attached to chromogenic dye forming insoluble dye substrate complex
Hydrolysis produces water-soluble dye-substrate fragments
CHROMOGENIC METHOD
50
Increase in color intensity of soluble dye-substrate solution
Color intensity proportional to AMY activity
Chromogenic method
51
CONTINUOUS-MONITORING
METHOD
Change in absorbance of_____ at _____
Optimal pH for AMY activity:____
NAD+ at 340 nm measured
6.9
52
SOURCES OF ERRORS
AMYLASE (AMY)
Stability of AMY (in serum and urine)
Inhibitors (Falsely Low AMS)
Medications
53
AMYLASE
Stability of AMY (in serum and urine)
Stable at room temperature for____
Stable at 4°C for____
1 week
2 months
54
AMYLASE
• Inhibitors (Falsely Low AMS):
• ^ Plasma triglycerides
• Wheat germ lectin
• Chelating agents (EDTA, Citrate, Oxalate)
55
AMYLASE
Medications
(Falsely † AMS):
Morphine and Opiates (Pain relief drugs)
56
AMYLASE (AMY)
Specimen handling
Specimen:_______
serum or heparinized plasma.
57
AMYLASE
Avoid saliva contamination (____times higher amylase content than serum)
______does not affect most methods except ________involving peroxidase reactions.
700
Hemolysis
coupled-enzyme methods
58
AMYLASE
Reference range:
Serum:
Urine:
28 to 100 U/L (37°C) (0.5 to 1.7 ukat/L)
1 to 15 U/h
59
NOMENCLATURE of LIPASE (LPS)
EC 3.1.1.3
Triacylglycerol acylhydrolase
60
Functions of LIPASE
Hydrolyzes ester linkages of fats
Produces alcohols and fatty acids
Targets fatty acid residues at positions 1 and 3 of triglyceride molecule
61
Accelerators of Lipase:
colipase and bile salts
62
Hydrolyzes ester linkages of fats
Produces alcohols and fatty acids
Targets fatty acid residues at positions 1 and 3 of triglyceride molecule
Lipase
63
LIPASE (LPS)
• Primary Source
• Secondary Sources
• Pancreas
• Stomach
• Small intestine
64
• Most specific marker of acute pancreatitis
LIPASE (LPS)
65
LIPASE (LPS)
• Comparison with Amylase (AMY)
• More specific for pancreatic disorders than AMY
• Both LPS and AMY levels rise quickly
• LPS elevations persist for ~ 8 days
• AMY elevations persist for only 2 to 3 days
66
RISES
AMYLASE
LIPASE
5-8hrs
4-8hrs
67
PEAKS
AMYLASE
LIPASE
24hrs
24hrs
68
Duration of Elevation
AMYLASE
LIPASE
3-5 days
7days
69
Normalize
AMYLASE
LIPASE
-
8-14 days
70
ASSAY FOR ENZYME ACTIVITY
LIPASE (LPS)
Early Methods
•Classic Cherry-Crandall Method
71
ASSAY FOR ENZYME ACTIVITY
LIPASE (LPS)
Modern Methods
• Turbidimetric Methods
• Colorimetric Methods
72
• Used olive oil substrate
• Measured liberated fatty acids by titration
• 24-hour incubation period
• Lacked stable and uniform substrates
Classic Cherry-Crandall Method
73
Classic Cherry-Crandall method
• Used _____substrate
• Measured liberated fatty acids by___
•_____incubation period
• Lacked stable and uniform substrates
olive oil
titration
24-hour
74
• Modified Cherry Crandall Method: use____ as substrate
Triolein
75
Lipase
• Simpler and more rapid
• Fats in solution create a cloudy emulsion
• Hydrolysis by LPS disperses particles
Rate of clearing measures LPS activity
Turbidimetric Methods
76
Lipase
• Based on coupled reactions with enzymes (e.g., peroxidase, glycerol kinase)
Colorimetric Methods
77
Colorimetric Methods
Examples of enzymes used
peroxidase, glycerol kinase
78
SOURCES OF ERRORS
LIPASE (LPS)
• Stability:
Stable in_____
• Negligible loss of activity:
• At room temperature for _____
• At 4°C for_____
serum
1 week
3 weeks
79
inhibits LPS activity
Causes falsely low values
Hemoglobin
80
SPECIMEN
LIPASE (LPS)
Serum/Plasma
81
LIPASE
• Reference range:
<38 U/L (37°C) (<0.6 pikat/L)
82
Other name of salivary amylase
Ptyalin
83
Other name of pancreatic amylase
Amylopsin
84
2 types of amylase
Amylose
Amylopectin
85
Breakdown from a-1,4 glycolysidic bonds produces
Glucose and maltose
86
Breakdown from a-1,6 glycolysidic bonds produces
Dextrin
87
Cellulose cannot be broken down by amylase bcs
B-1,4
88
Enzymes used in continuous monitoring method
Amylasr
a-glucosidase
Hexokinase
G-6-PD
89
Maltopentose + AMS =
Maltrotriose + maltose
90
Maltrotriose + maltose + a-glucosidase
5-Glucose + 5 ATP
91
5-Glucose + 5 ATP + Hexokinase
5-Glucose-6-phosphate + 5 ADP
92
5-Glucose-6-phosphate + 5 NAD + G6PD
5,6-Phosphogluconolactone + 5 NADH
93
Continuous Monitoring method is measured by using…
Spectrophotometry
94
Tubes that can be used for AMS
Red
Gold
Green
95
For AMS, and coupled enzyme method is nit used, is it okay to accept hemolyzed sample?
Yes
96
AMS sample
Fresh serum/ plasma (free if hemolysis)
Urine (1/3 diluted)
97
Alpha-Amylase Activity formula
(Change in absorbance/min.) x 3178
U/L
98
Amylase reference range agappe
Serum/ plasma: 35-86 U/L
Urine: < 470 U/L
99
Coenzyme of lipase
Colipase
100
Rate of clearing is measured
LPS
Turbidimetric method
101
Room temp
20-25C
