Enzyme Behavior

Question 1

What are keynotes for enzymes?

Answer 1

Enzymes significantly increase the rate of biochemical reactions
They are specific for their substrates
Enzyme activity can be regulated by factors such as inhibitors, activators, or changes in environmental conditions
THEY DONT ALTER EQUILIBRIUM

Question 2

What are the “Standard state conditions”?

Answer 2

Temp: 25C (298 K)
Molarity: 1 M
Pressure: 1 atm
(pH): 7

Question 3

How are enzymes related to activation energy and transition state?

Answer 3

Enzymes speed up reactions by lowering the activation energy, enzymes stabilize the transition state to lower this barrier.

Question 4

How are enzymes related to temperature?

Answer 4

Reaction rates increase with temperature, but too high a temperature can denature the enzyme, rendering it inactive.

Question 5

What are the two ways to express enzyme reaction rate?

Answer 5

-The loss of substrate concentration over time
-The increase in product concentration over time

Question 6

What is the concept of the rate (proportionality) constant?

Answer 6

In enzyme kinetics, the rate constant k relates the reaction rate to the concentration of the reactants (substrates).

Question 7

How do you determine the reaction order? How do you determine the overall order of a reaction?

Answer 7

The overall order of the reaction is the sum of the exponents in the rate law

Question 8

What constitutes a zero-order reaction?

Answer 8

A zero-order reaction means that the rate of reaction is independent of the concentration of the substrate
Enzyme-catalyzed reactions can reach a zero-order state when the substrate concentration is much higher than the enzyme concentration

Question 9

What are the types of intermolecular bonding seen in enzymatic activity?

Answer 9

-Hydrogen bonds
-Ionic bonds
-Van der waals forces

Question 10

What are the two enzyme-substrate binding models?

Answer 10

-Lock and Key Model: Substrate is a perfect fit
-Induced Fit Model: The active site adapts its shape to the substrate

Question 11

What is the ES complex?

Answer 11

Formation of the ES (Enzyme-substrate) Complex lowers the energy barrier between the substrate and the transition state, facilitating product formation.

Question 12

What are the three rate constants of one substrate and one product reactant?

Answer 12

K1: The rate of formation of the enzyme-substrate complex (ES)
K-1: The rate of dissociation of the enzyme-substrate complex (ES)
K2: The rate of the conversion of the enzyme-substrate complex (ES) into the enzyme (E) and the product (P).

Question 13

What is Km?

Answer 13

Km is an equilibrium constant It provides insight into the substrate’s affinity for the enzyme
Low Km = High Affinity
High Km = Low Affinity

Question 14

What are different amounts of substrate concentration linked to? (Kinetics)

Answer 14

First-order kinetics at Low [S]
Zero-order kinetics at High [S]

Question 15

What is the definition of steady-state kinetics

Answer 15

Rate of formation of ES = rate of breakdown of ES
(No changes in ES over time)

Question 16

What would higher enzyme concentration cause?

Answer 16

Higher reaction velocity

Question 17

What is the Michaelis-Menten Equation?

Answer 17

Initial Velocity = Max velocity x [S]/ Km + [S]

Question 18

What are key points of about Km and Vmax?

Answer 18

1. Km is a collection of rate constants
2. When S»>E, the enzyme is mostly in the form of the ES complex.

Question 19

How are Km and Vmax related?

Answer 19

Km is half of Vmax (VALUE ON THE X-AXIS IDIOT)

Question 20

What is Kcat?

Answer 20

Kcat is a measure of an enzyme’s catalytic speed (It’s equal to K2) (Tells us how fast an enzyme can turn a substrate into a product)

Question 21

What is a Bi-Bi reaction?

Answer 21

Bi-Bi reactions involve two substrates and two products

Question 22

What are the three main types of Bi-Bi reactions?

Answer 22

Ordered Bi-Bi Reactions: Substrates bind to the enzyme in a specific sequence, and products are released in a specific order.
Random Bi-Bi Reactions: Substrates can bind to the enzyme in any order, and products can be released in any order.
Ping-Pong Bi-Bi Reactions: The enzyme changes between two different states to produce 2 different products

Question 23

What is an inhibitor? What is a reversible inhibitor?

Answer 23

Inhibitors decrease the rate of an enzyme-catalyzed reaction.
Reversible inhibitors are inhibitors that can be reversed (Cmon now)

Question 24

What is KI? What does it tell us?

Answer 24

KI is the Inhibition Constant and it tells us the affinity of the enzyme for the inhibitor
Higher KI = Lower affinity
Lower KI = Higher affinity

Question 25

How does competitive inhibition affect Vmax and Km

Answer 25

Vmax remains unchanged, Km increases

Question 26

How does non-competitive inhibition affect Vmax and Km

Answer 26

Vmax decreases and Km Remains unchanged

Question 27

On a Lineweaver-Burk graph, what does it look like? Where can you find Vmax and Km? How can you find Vmax and Km?

Answer 27

A Lineweaver-Burk graph is identified by a straight line, Vmax can be found by looking at the inverse of the y-intercept and Km can be found by looking at the -inverse of the x-intercept