Enzymes: Amylase/Lipase

Question 0

What reaction does alpha amylase catalyze?

Answer 0

Catalyzes the hydrolysis of alpha-1,4-glycosidic bonds in polymers of glucose

Question 1

What are the 2 types of amylase?

Answer 1

Beta and alpha

Question 2

What is the cofactor required for amylase catalytic activity?

Answer 2

Calcium

Question 3

What is the pH optimum for amylase catalytic activity?

Answer 3

6.9-7.0

Question 4

Is it normal to find amylase in the urine?

Answer 4

Yes, amylase is small enough to be filtered by the glomerulus of the kidney

Question 5

What are activators for amylase activity?

Answer 5

Univalent anions, such as Chloride or Bromide

Question 6

Amylase is inhibited by all anticoagulants except:

Answer 6

Heparin

Question 7

How long is amylase stable at room temperature?

Answer 7

1 week

Question 8

How long is amylase stable at refrigerated temperature?

Answer 8

2 months

Question 9

What is endoamylase?

Answer 9

Hydrolysis occurs at random locations in the polysaccharide

Question 10

What sort of amylase is endoamylase?

Answer 10

Alpha amylase

Question 11

What is exoamylase?

Answer 11

Enzyme found in plants and bacteria only. It acts only on the bonds at the terminal end of a glucose chain.

Question 12

What type of amylase is exoamylase?

Answer 12

Beta amylase

Question 13

If a specimen needs to be diluted for amylase measurement, what do you need to use to dilute it?

Answer 13

Saline

Question 14

In amylase measurement, why does saline need to be used instead of water?

Answer 14

If water is used, chloride will be diluted considerably. Chloride is needed to activate the reaction catalyzed by amylase.

Question 15

Where is amylase found?

Answer 15

Found in many tissues throughout the body

Question 16

Where are the highest amylase concentrations found?

Answer 16

Pancreas and salivary glands

Question 17

How many salivary isoenzymes are there?

Answer 17

3 - S1, S2, S3

Question 18

How many pancreatic isoenzymes are there?

Answer 18

3 - P1, P2, P3

Question 19

Amylase is stable until what temperature is reached?

Answer 19

50 degrees Celsius

Question 20

How is the pain associated with acute pancreatitis caused?

Answer 20

Proteolytic enzymes are released throughout the pancreas, causing tissue destruction and leading to the epigastric pain. This is called autolysis.

Question 21

Why does amylase increase so drastically in acute pancreatitis?

Answer 21

The autolysis associated with the proteolytic enzymes causes a release of pancreatic amylase into the serum.

Question 22

When does serum amylase increase in acute pancreatitis?

Answer 22

5-8 hours after disease onset

Question 23

When do serum amylase levels peak in acute pancreatitis?

Answer 23

They peak with 24 hours of disease onset

Question 24

When do serum amylase levels return to normal after an attack of acute pancreatitis?

Answer 24

Return to normal range in 3-5 days

Question 25

When do urine amylase levels return to normal after an attack of acute pancreatitis?

Answer 25

Will remain elevated for up to 10 days

Question 26

What disease states is acute pancreatitis associated with?

Answer 26

Alcoholism, hyperlipemia, uremia, hyperparathyroidism, trauma

Question 27

Is the serum amylase level specific for pancreatitis?

Answer 27

Serum amylase levels can be elevated in a wide variety of disease states

Question 28

What is macroamylasemia?

Answer 28

Amylase will complex with immunoglobulins, forming a large complex that can not be cleared from the serum by the kidneys

Question 29

What immunoglobulins will amylase complex with when macroamylasemia is present?

Answer 29

IgG or IgA

Question 30

In macroamylasemia, will serum amylase be increased, decreased, or normal?

Answer 30

Increased

Question 31

In macroamylasemia, will urinary amylase be increased, decreased, or normal?

Answer 31

Normal or decreased

Question 32

How can macroamylasemia and acute pancreatitis be differentiated?

Answer 32

Calculate the amylase clearance/creatinine clearance ratio

Question 33

What is the formula for the amylase clearance/creatinine clearance ratio?

Answer 33

(Urine amylase x serum creatinine)/(serum amylase/urine creatinine) x 100%

Question 34

What is the normal ACCR?

Answer 34

2-5%

Question 35

If the ACCR is less than 2%, what does this indicate?

Answer 35

Macroamylasemia

Question 36

If the ACCR is increased, what does this indicate?

Answer 36

Acute pancreatitis

Question 37

What is the modified saccharogenic method?

Answer 37

A polysaccharide is hydrolyzed by amylase to form reducing sugars. The increasing levels of reducing sugars are measured using the hexokinase method.

Question 38

What must be corrected for in the modified saccharogenic method?

Answer 38

Endogenous glucose, which will falsely increase the results

Question 39

How do you correct for endogenous glucose in the modified saccharogenic method?

Answer 39

Use a serum blank and subtract glucose from the blank from the result. Or you can allow 10 minutes preincubation to allow glucose in the sample to react.

Question 40

What type of amylase normally dominates in the serum?

Answer 40

S type

Question 41

What type of amylase dominates normally in the urine?

Answer 41

P type

Question 42

How would you further differentiate amylase isoenzymes?

Answer 42

Use isoenzyme fractionation

Question 43

What methods can be used for amylase isoenzyme fractionation?

Answer 43

Electrophoresis, isoelectric focusing, chemical inhibition, inhibition of salivary amylase with monoclonal antibodies

Question 44

During isoenzyme fractionation, amylase enzymes of which origin will migrate the fastest?

Answer 44

Salivary origin

Question 45

What are the most commonly observed amylase isoenzyme fractions?

Answer 45

P2, S1, S2

Question 46

In acute pancreatitis, what amylase isoenzyme is predominant?

Answer 46

P3

Question 47

What reaction does lipase catalyze?

Answer 47

Lipase catalyzes the hydrolysis of dietary triglycerides with long chain fatty acids.

Question 48

What is required by lipase for optimal activity?

Answer 48

Colipase, protein secreted by the pancreas