Clinical Chemistry (Clinical Enzymology)

Front 1

Enzymes

Back 1

-Biocatalysts

-Macromolecules

-Strictly confined inside the cell

-Used as markers for cell / tissue injury or damage

-Measured based on their activity

Front 2

Apoenzyme

Holoenzyme

Active site

Allosteric site

Back 2

What are the enzyme structures?

Front 3

Apoenzyme is the protein portion of an enzyme

Back 3

Define apoenzyme

Front 4

Holoenzyme is the complete functional enzyme (apoenzyme + prosthetic group)

Back 4

Define holoenzyme

Front 5

Active site is where the substrate attaches

Back 5

Define Active Site

Front 6

Allosteric site is where regulatory molecule bind

Back 6

Define Allosteric Site

Front 7

1. Emil Fisher's Lock and Key Theory

2. Kochland's Induced Fit Theory

Back 7

What are the two enzyme theories?

Front 8

1. Change in substrate concentration

2. Change in coenzyme concentration

3. Change in product concentration

Back 8

What are the basis in measuring enzymatic activity?

Front 9

1. Fixed-time

2. Continuous Monitoring

Back 9

What are the approaches in measuring enzyme activity?

Front 10

Fixed-time

Back 10

- the reactants are combined and the reaction is allowed to proceed at a specified time

- products formed are measured over a given amount of time

- rate of reaction is directly proportional to enzyme concentration

Front 11

Continuous Monitoring

Back 11

- Multiple measurements are made usually based on change in absorbance

- measurements are made during the reaction either at given time intervals or continuous by a continuous reading spectrophotometer

- preferred method because deviation in linearity is easily identifiable

Front 12

- Rate of reaction is dependent on substrate concentration

- This happens if the substrate concentration is less than the enzyme concentration

Back 12

Define the First Order Kinetics

Front 13

- Rate of reaction is dependent on enzyme concentration

- This happens if the enzyme concentration is less than the substrate concentration

Back 13

Define the Zero Order Kinetics

Front 14

Alkaline and acidic

Back 14

Excessive ________ pH can affect and can denature enzymes.

Front 15

Physiological blood pH

Back 15

Optimum working pH is the _________, however some perform with pH requirements.

Front 16

37°C

Back 16

Optimum working temperature

Front 17

40-50°C

Back 17

Temperature where rate of denaturation increases.

Front 18

56°C

Back 18

Temperature where there is a complete denaturation.

Front 19

-20°C

Back 19

Enzyme storage temperature

Front 20

2°C to 8°C

Back 20

Substrate and coenzyme storage temperature

Front 21

Directly

Back 21

ENZYME CONCENTRATION

- Rate of reaction is ________ proportional with enzyme concentration in the presence of excess substrate.

Front 22

Higher ; no longer increase

Back 22

SUBSTRATE CONCENTRATION

- The higher the substrate concentration, the ______ the rate of reaction, however when all enzymes are bound with a substrate, the rate will ________.

Front 23

Substances that enhance enzyme function

Back 23

Define Cofactors

Front 24

1. Coenzymes

- organic

- NAD/NADH, pyridoxal phosphate

2. Activators

- inorganic

- electrolytes

Back 24

What are the 2 cofactors?

Front 25

Substances that decrease enzyme reaction

Back 25

Define inhibitors

Front 26

1. Competitive inhibitor

2. Noncompetitive inhibitor

3. Uncompetitive inhibitor

Back 26

What are the 3 types of inhibitors?

Front 27

The inhibitor that competes with the substrate for the same binding site

Back 27

Define competitive inhibitor

Front 28

The inhibitor that binds the enzyme on sites other than the active site.

Back 28

Define Noncompetitive inhibitor

Front 29

The inhibitor that attaches the enzyme - substrate complex

Back 29

Define Uncompetitive Inhibitor

Front 30

1. Substrate addition

- reverses competitive inhibition

- no effect to Noncompetitive inhibition

- intensifies Uncompetitive Inhibition

2. Sample dilution

- can reverse all type of inhibitions

Back 30

What are the remedies for inhibition?

Front 31

- Different enzyme forms that maintains the same catalytic function throughout the body

- May be differentiated from each other based on certain properties such as electrophoretic mobility, solubility, or resistance to inactivation.

Back 31

Define Isoenzymes

Front 32

1. Oxidoreductases

2. Transferases

3. Hydrolases

4. Lyases

5. Isomerases

6. Ligases

Back 32

What are the different enzyme classifications?

Front 33

Lactate dehydrogenase

Back 33

What is considered as the least specific enzyme?

Front 34

Pernicious/megaloblastic anemia

Back 34

Highest elevation of LD is often seen in _________.

Front 35

LD6

Back 35

- alcohol dehydrogenase

- present in arteriosclerotic cardiovascular failure

- seen together with LD5 increase

Front 36

LD - Flipped Pattern

Back 36

- LD1>LD2

- Hemolytic anemia and myocardial infarction

Front 37

Duchenne's muscular dystrophy

Back 37

Highest elevation or CK is seen in _________.

Front 38

Adenylate kinase

Back 38

In CK, hemolysis must be avoided due to the presence of _________ inside RBCs which mimics CK activity.

Front 39

Acute viral hepatitis

Back 39

Highest elevation of Alanine aminotransferase is seen in _______.