Test 2: Diagnostic Enzymology

Question 1

Enzymes are mainly _________ that facilitate biochemical reactions.

Answer 1

proteins

-ribozymes: RNA splicing

Question 2

Purpose of measuring enzymes?

Answer 2

-Can measure the ACTIVITY of these enzymes in the blood to ascertain whether these organs have been or are being damaged.
-Abnormal serum enzyme levels are found in various diseases and
inflammation

Question 3

What are the types of inhibition for enzyme activity?

Answer 3

1) Competitive inhibition
2) Allosteric inhibition
3. pH
4.Temperature
5.Presence of Inhibitor

Question 4

• Inactive or less active precursor of enzyme
  -Proteolytic modification required to be activated

Answer 4

Proenzyme (Zymogen)

Question 5

Examples of Proenzyme (Zymogen)?

Answer 5

Angiotensinogen,
trypsinogen, pepsinogen,
chymotrysionogen, prolipase

Question 6

Enzymes work by converting a substrate into a product via an ______________.

Answer 6

enzyme-substrate complex

Question 7

Km =

Answer 7

(K-1 + K2) / K1

= Dissociation / Association

Question 8

How dose enzymes speed up reactions?

Answer 8

-by lowering activation energy
-Increasing “rate constant”
-increasing “Substrate specificity” (or Substrate concentration)

Question 9

Endergonic or exergonic:

If delta G is positive? If negative?

Answer 9

Endergonic

Exergonic

Question 10

Reaction rate = K[S]x[S]y

What is the rate constant?

Answer 10

K

Question 11

What are the factors influencing the rate of reaction?

Answer 11

1.Enzyme concentration
2.Substrate Concentration

Question 12

increased [substrate], the rate of reaction ___________.

Answer 12

increases

• But [substrate] too high, enzyme Saturation

Question 13

The shape of the protein affects its _________

Answer 13

activity

-Anything that alters the conformation of the
protein/enzyme will have an impact on its activity.

Question 14

enzymes require a pH of 7-8. What are some exceptions?

Answer 14

alkaline phosphatase, acid phosphatase, pepsin

Question 15

How are single (end) point assays done?

Answer 15

• Incubate sample with substrate for a period of time
• Measure the end absorbance (O.D.)
• Calculate enzyme level by comparing to the [STD]

Question 16

How are kinetic assays done?

Answer 16

• Incubate sample with substrate
• Measure the absorbance over time at certain increments
• An average change in absorbance (product formation) is
  used to calculate “enzyme activity”

Question 17

IU or U =

Answer 17

The amount of enzyme that produces 1μM of product per minute under standard conditions

Question 18

Use _________ to convert absorbance to μM

Answer 18

molar absorptivity

Question 19

How do you calculate enzyme activity?

Answer 19

Δ absorbance / molar absorptivity x dilution factor

total volume / sample volume