Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MLS 421 Clinical Chemistry II > Enzymes & Kinetics > Flashcards

Enzymes & Kinetics Flashcards

1
Q

What are some general properties of enzymes?

A

Enzymes are proteins with catalytic activity which increase the rate of a chemical reaction without being consumed; exhibit stereospecificity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the energy of activation in a reaction?

A

The amount of energy it takes for a reaction to occur.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the six enzyme classifications?

A

(1) Oxidoreductases
(2) Transferases
(3) Hydrolases
(4) Lyases
(5) Isomerases
(6) Ligases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some characteristics of isoenzymes?

A

They catalyze the same reaction as enzymes, but they can exist in a different form. They can exist due to different amino acid composition, different physical properties, and different enzymatic properties.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Complete the following equation:

_____ (active form) = _____ (inactive form) + _____

A

Holoenzyme Activity = Apoenzyme Activity + Cofactor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define cofactor(s).

A

non-protein molecule conjugated to an enzyme.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are examples of cofactors?

A

Essential ions, coenzymes, inorganic and organic, Ca, Cl-, Mg+, NADH, NADPH.

Digestive Enzymes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define Prosthetic Group.

A

A tightly bound cofactor. E.g. heme bound to peroxidase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are factors influencing enzyme activity?

A

Temperature, pH, Activators (cofactors), inhibitors, substrate concentration, and enzyme concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the temperature of the reaction effect the activity?

A

As temperature increases, activity will increase until the optimum temperature is reached, then denaturation of the protein will occur.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is activity of an enzyme reaction affected by activators and inhibitors?

A

Activators (cofactors) enhance the reaction (reaches max velocity the fastest).

Inhibitors delay the reaction (reaches the max velocity the slowest).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the concentration of the substrate affect the enzyme reaction?

A

Reaction velocity is dependent on substrate concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

During zero order kinetics, at saturating {S}, velocity is ___ of substrate concentration and ___ proportional to {E} enzyme concentration.

A

independent; directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define competitive inhibitor.

A

Binds at the active site and competes with the substrate for binding sites.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is Km and Vmax altered during competitive inhibition?

A

Raises Km; Vmax is unaffected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What kind of inhibitor represents this graph?

A

Competitive Inhibitor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define noncompetitive inhibitor.

A

Binds at an allosteric or regulatory site, which may be at or far removed from the active site.

18
Q

How is Km and Vmax altered during noncompetitive inhibition?

A

Km is unaffected; Vmax decreases.

19
Q

What kind of inhibitor represents this graph?

A

Noncompetitive Inhibitor

20
Q

Define uncompetitive inhibitor.

A

Binds to the enzyme-substrate complex and not to free enzyme; prevents product formation.

21
Q

How is Km and Vmax altered during uncompetitive inhibition?

A

Lowers Km; Lowers Vmax; Vmax/Km unchanged.

22
Q

What kind of inhibitor is represented by this graph?

A

Uncompetitive inhibitor.

23
Q

Define irreversible inhibition.

A

An inhibitor that binds specifically to the active site; forms stable covalent bond with enzyme inactivating it.

24
Q

Enzyme measurement is dependent on what?

A

Temperature and pH changes, activator concentration, inhibitor concentration, and substrate concentration.

25
Q

How are enzymes measured?

A

By activity, not concentration. It measures the rate or velocity.

26
Q

What is the international unit for measuring enzymes?

A

U: the amount of enzyme that catalyzes 1 umol of substrate per minute at standard conditions.

27
Q

NADH is measured at what wavelength?

A

340nm.

28
Q

What are the three phases of first order kinetics, and what do they do?

A

(1) Lag phase: E + S
(2) Linear phase, zero order: E + S = P; {S} is high and enzyme is saturated with substrate. Product formation is constant.
(3) Depletion phase: A plateau is reached; Vmax has been reached. The reaction rate reduces due to: ↓ [S], equilibrium of reaction, product inhibition, and pH changes.

29
Q

In zero order kinetics, when should enzyme activity be measured?

A

At saturating [S] (phase 2 - linear phase).

30
Q

In zero order kinetics, velocity is ___ of substrate concentration and ___ proportional to [E].

A

independent; directly

31
Q

When is there a deviation from linearity occur in enzyme reactions?

A

Due to high concentrations of enzymes, depletion of available substrate, and multiple readings of absorbance are missed because of the fast reaction rate.

32
Q

How can you solve deviation from linearity for an enzyme reaction?

A

By diluting the sample.

33
Q

Enzyme activity is calculated based on what?

A

Molar absorptivity of NADH, change in absorbance over time, volume, Beer’s law.

34
Q

Enzymatic reactions can be used to quantitate what analytes?

A

Glucose, cholesterol, and uric acid.

35
Q

Define absolute specificity.

A

One substrate, one reaction.

36
Q

Define group specificity.

A 
Reactions with a certain class of molecules. 
E.g. ACP can hydrolyze beta glycerol phosphate.
37
Q

Define stereoisomeric specificity.

A

Specific for one optical isomer.

38
Q

How does sex alter specimens?

A

Differences related to muscle mass, exercise or hormone concentration.

39
Q

How does age alter specimens?

A

Variations occur during first year of life, puberty, and late to middle age.

40
Q

How does exercise CK-MM?

A

Increases.

41
Q

What analytes are affected by hemolysis?

A

LD, ALP, AMS, ALT, AST, GGT, ACP.

MLS 421 Clinical Chemistry II (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions