[LAB] AST/ALT

Question 1

→ Biologic proteins that catalyze chemical reactions without being consumed.

Answer 1

enzymes

Question 2

→ They speed up reactions without altering equilibrium or being changed.

Answer 2

enzymes

Question 3

What are the six major classes of enzymes?

Answer 3

→ Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, Ligases.

Question 4

What type of enzyme is aspartate aminotransferase (AST)?

Answer 4

Transferase

Question 5

What type of enzyme is lactate dehydrogenase (LD)?

Answer 5

Oxidoreductase

Question 6

→ It transfers functional groups between molecules.

Answer 6

transferase

Question 7

Where are enzymes commonly found in the body?

Answer 7

→ In all body tissues and frequently in serum after cellular injury.

Question 8

→ The substance that an enzyme acts upon.

Answer 8

substrate

Question 9

→ The region where the substrate binds and the reaction occurs.

Answer 9

active site

Question 10

→ A site other than the active site where regulatory molecules bind.

Answer 10

allosteric site

Question 11

What is the International Unit (IU) of enzyme activity?

Answer 11

→ The amount of enzyme that catalyzes 1 µmol of substrate per minute.

Question 12

What is the SI unit for enzyme activity?

Answer 12

→ Katal (mol/s).

Question 13

What is the standard unit for enzyme concentration in the lab?

Answer 13

→ IU/L or kat/L.

Question 14

What is the conversion factor between IU and nkat?

Answer 14

→ 1.0 IU = 17 nkat.

Question 15

What reaction order is enzyme activity measured at in the lab?

Answer 15

→ Zero-order kinetics.

Question 16

What are some conditions that must be controlled in enzyme assays?

Answer 16

→ pH, temperature, and absence of inhibitors.

Question 17

What are the two main types of enzyme measurement methods?

Answer 17

→ Kinetic and endpoint methods.

Question 18

What does an increase in enzyme absorbance indicate in a kinetic assay?

Answer 18

→ Increased enzyme activity.

Question 19

What reaction does AST catalyze?

Answer 19

→ The transfer of an amino group between aspartate and α-ketoglutarate.

Question 20

What coenzyme is required for AST activity?

Answer 20

→ Pyridoxal phosphate.

Question 21

What are the major tissue sources of AST?

Answer 21

→ Liver, cardiac tissue, skeletal muscle, kidney, pancreas, erythrocytes.

Question 22

What are the two AST isoenzymes?

Answer 22

→ Cytoplasmic AST and Mitochondrial AST.

Question 23

What laboratory method is commonly used to measure AST?

Answer 23

→ The Karmen method.

Question 24

It is a coupled enzymatic reaction that measures absorbance change at 340 nm.

Answer 24

Karmen method

Question 25

What wavelength is used to measure AST in the Karmen method?

Answer 25

→ 340 nm.

Question 26

What reagent is used in the Reitman-Frankel AST method?

Answer 26

→ 2,4-Dinitrophenylhydrazine (DNPH).

Question 27

What is the color change in the Reitman-Frankel AST method?

Answer 27

→ Intense brown.

Question 28

What is the normal reference range for AST levels?

Answer 28

→ 6-37 U/L (37°C).

Question 29

What is another name for ALT?

Answer 29

→ Serum glutamate-pyruvate transaminase (SGPT).

Question 30

What reaction does ALT catalyze?

Answer 30

→ The transfer of an amino group from alanine to α-ketoglutarate.

Question 31

What coenzyme is required for ALT function?

Answer 31

→ Pyridoxal phosphate.

Question 32

What are the primary tissue sources of ALT?

Answer 32

→ Liver and cardiac tissue.

Question 33

What laboratory method is commonly used to measure ALT?

Answer 33

→ The Karmen method.

Question 34

What is the indicator enzyme in the Karmen method for ALT?

Answer 34

→ Lactate dehydrogenase (LD).

Question 35

What reagent is used in the Reitman-Frankel ALT method?

Answer 35

→ 2,4-Dinitrophenylhydrazine (DNPH).

Question 36

What is the final product detected in the Reitman-Frankel ALT method?

Answer 36

→ Ketoacid hydrazone.

Question 37

What is the reference range for ALT levels?

Answer 37

→ 6-37 U/L (37°C).

Question 38

What laboratory factors can falsely elevate ALT levels?

Answer 38

→ Bilirubin, erythromycin, iproniazid, morphine, endogenous pyruvate.

Question 39

What factors can falsely decrease ALT levels?

Answer 39

→ Presence of heavy metals like mercurial diuretics.

Question 40

all enzymes we measure are found in the ____

Answer 40

serum

Question 41

AST Substrate: ALT Substrate:

Answer 41

L-aspartate L-alanine

Question 42

Indicator enzyme in AST

Answer 42

Malate dehydrogenase

Question 43

When NADH is oxidized to NAD+ in the karmen method, the absorbance is (increased/decreased)

Answer 43

Decreased

Question 44

Optimal pH for AST/LT method

Answer 44

7.0 - 8.0

Question 45

AST are found to be decreased in the _________

Answer 45

urethra kaya decreased in uremia

Question 46

Most common AST isoenzyme

Answer 46

Cell cytoplasm AST

Question 47

If you have necrosis, what AST isozenzyme increases?

Answer 47

Mitochondrial AST

Question 48

pH must be at least close to the _______'s pH

Answer 48

Body's pH (7.4)

Question 49

Non-CHON molecule of enzymes necessary for enzyme activity

Answer 49

Co-factors

Question 50

Activator (INORGANIC) / Co-enzymes (ORGANIC): Chloride, bromide, magnesium, iron, zinc, copper, calcium, manganesem cobalt, potassium

Answer 50

Activator/Organic

Question 51

2.6.1.1 What is 2?

Answer 51

Class

Question 52

2.6.1.1 What is 6?

Answer 52

Sub group

Question 53

2.6.1.1 What is the first 1?

Answer 53

sub-sub group

Question 54

2.6.1.1 What is the second 1?

Answer 54

serial number

Question 55

2.6.1.1 What is this enzyme?

Answer 55

Aspartate aminotransferase (AST)

Question 56

breakage of bonds with hydrolysis

Answer 56

Hydrolases

Question 57

breakage of bonds without hydrolysis

Answer 57

Lyases

Question 58

classification of the enzyme where there conversion of geometric or position of isomers

Answer 58

Isomerases

Question 59

Class no: Oxidoreductases

Answer 59

1

Question 60

Class no: Transferases

Answer 60

2

Question 61

Class no: Hydrolases

Answer 61

3

Question 62

Class no: Lyases

Answer 62

4

Question 63

Class no: Isomerases

Answer 63

5

Question 64

Class no: Ligase

Answer 64

6