Unit 2 Aminotransferases

Question 1

What are biologic proteins that facilitate chemical reactions without being altered?

Answer 1

Enzymes.

Question 2

How do enzymes help indicate organ health?

Answer 2

They are present in serum after cellular damage.

Question 3

How is enzyme concentration assessed?

Answer 3

By measuring their activity in a reaction.

Question 4

What is a molecule that an enzyme acts upon during a reaction?

Answer 4

A substrate.

Question 5

Where does the substrate bind and the reaction occur on an enzyme?

Answer 5

The active site.

Question 6

What part of an enzyme regulates its activity by binding specific molecules?

Answer 6

The allosteric site.

Question 7

How do enzymes interact with specific substrates?

Answer 7

Through the lock and key model.

Question 8

Which enzymes facilitate oxidation-reduction reactions?

Answer 8

Oxidoreductases.

Question 9

Which class of enzymes transfers functional groups between molecules?

Answer 9

Transferases.

Question 10

Which enzymes break chemical bonds using water?

Answer 10

Hydrolases.

Question 11

Which enzymes break chemical bonds without using water?

Answer 11

Lyases.

Question 12

Which enzymes rearrange molecular structures?

Answer 12

Isomerases.

Question 13

Which enzymes create bonds between molecules?

Answer 13

Ligases.

Question 14

What influences the activity of enzymes?

Answer 14

Temperature, pH, and molecular interactions.

Question 15

How does a 10°C increase affect enzyme activity?

Answer 15

It can double the reaction rate before denaturation.

Question 16

What pH range do most enzymes function best at?

Answer 16

Slightly basic (7.0-8.0).

Question 17

What non-protein molecules assist enzyme function?

Answer 17

Cofactors.

Question 18

Which cofactors include magnesium, iron, and calcium ions?

Answer 18

Inorganic cofactors.

Question 19

Which cofactors include Coenzyme A, biotin, and thiamine pyrophosphate?

Answer 19

Organic cofactors.

Question 20

What reduces enzyme activity by interfering with substrate binding?

Answer 20

Enzyme inhibitors.

Question 21

How is enzyme function evaluated?

Answer 21

By monitoring changes in product, substrate, or coenzyme levels.

Question 22

In which kinetic state is enzyme activity independent of concentration?

Answer 22

Zero-order kinetics.

Question 23

In which kinetic state does enzyme activity depend on concentration?

Answer 23

First-order kinetics.

Question 24

What represents the amount of enzyme needed to catalyze 1 µmol of substrate per minute?

Answer 24

An International Unit (IU).

Question 25

Which clinical enzymes are commonly measured?

Answer 25

AST, ALT, ALP, and CK, among others.

Question 26

Which enzyme transfers amino groups between aspartate and α-keto acids?

Answer 26

Aspartate Aminotransferase (AST).

Question 27

What was formerly known as Serum Glutamic Oxaloacetic Transaminase (SGOT)?

Answer 27

AST.

Question 28

Where is AST primarily located in the body?

Answer 28

The heart, liver, muscles, kidneys, pancreas, and red blood cells.

Question 29

When do AST levels increase?

Answer 29

During heart attacks, liver disease, and muscle disorders.

Question 30

What condition is associated with decreased AST levels?

Answer 30

Uremia.

Question 31

Which method measures AST using NADH oxidation at 340 nm?

Answer 31

The Karmen method.

Question 32

Which technique uses 2,4-dinitrophenylhydrazine (DNPH) for AST detection?

Answer 32

The Reitman-Frankel method.

Question 33

Which enzyme transfers an amino group from alanine to α-ketoglutarate?

Answer 33

Alanine Aminotransferase (ALT).

Question 34

What was previously known as Serum Glutamic Pyruvate Transaminase (SGPT)?

Answer 34

ALT.

Question 35

Where is ALT most commonly found?

Answer 35

The liver and cardiac tissues.

Question 36

When does ALT increase?

Answer 36

During liver disease, heart failure, and muscle conditions.

Question 37

Which enzyme is more specific for liver function?

Answer 37

ALT.

Question 38

What is the normal AST range for men?

Answer 38

Up to 35 U/L at 37°C.

Question 39

What is the normal AST range for women?

Answer 39

Up to 31 U/L at 37°C.

Question 40

What is the normal ALT range for men?

Answer 40

Up to 22 U/L at 37°C.

Question 41

What is the normal ALT range for women?

Answer 41

Up to 17 U/L at 37°C.

Question 42

What can artificially alter ALT readings?

Answer 42

Bilirubin, erythromycin, and other substances.

Question 43

Which enzymatic method is commonly used for ALT measurement?

Answer 43

The Karmen method with lactate dehydrogenase.

Question 44

At what wavelength is enzymatic activity typically monitored?

Answer 44

340 nm.

Question 45

Why should hemolysis be avoided in AST and ALT assays?

Answer 45

Intracellular enzymes are released, leading to false high readings.

Question 46

Why is TRIS buffer important in AST assays?

Answer 46

It maintains a stable pH environment for reactions.

Question 47

Why must the working reagent be added at the right time?

Answer 47

Because enzymatic activity starts immediately, affecting accuracy.

Question 48

What enzyme helps measure AST by converting oxaloacetate to malate?

Answer 48

Malate dehydrogenase.

Question 49

Which enzyme assists ALT measurement by converting pyruvate to lactate?

Answer 49

Lactate dehydrogenase.