Chapter 4: Enzyme Kinetics Flashcards
1
Q
Enzyme kinetics
A
- Investigation of rates of enzyme-catalyzed reactions
- Help determine substrate specificity and reaction mechanisms
2
Q
Establishes the initial rate of reaction
A
- Measuring either the disappearance of substrate or the appearance of product per unit time
3
Q
Progressive curve
A
- The time course of an enzyme-catalyzed reaction
- Concentration on y-axis
- Time on x-axis
4
Q
Maximum velocity of enzyme (Vmax)
A
- The point where the enzyme the enzyme is saturated with substrate (all enzyme in ES form) and very little free enzyme exists
5
Q
Initial reaction rates (Vo)
A
- Measured by drawing a tangent to the hyperbolic plot of [product] formed vs time when t = 0
6
Q
Progress cruve (Vo) is at maximum
A
- Substrate supplies are high and a minimal amount of product has been formed
- Makes reverse reaction insignificant
7
Q
High enzyme concentration effect on initial rate
A
- Initial rate will be higher at high enzyme concentration than at low enzyme concentration
- More product is formed as time increases for each enzyme when substrate is in excess
8
Q
Gradient of slope
A
- Calculates the amount of product formed per unit time
9
Q
Calculate initial rate (Vo)
A
- Can be determined by measuring the gradient at t = 0
10
Q
First order kinetics
A
- At low concentrations or substrate, a rapid increase in reaction velocity that is proportional to [S] is observed
11
Q
Zero order kinetics
A
- At high [S] the curve plateaus at a maximum value (Vmax)
- Reaction velocity is independent of changes in [S]
12
Q
Temperature
A
- Reaction rate initially increases when this increases as the enzyme is activated
13
Q
Denaturation of the enzyme
A
- Occurs when the non-covalent stabilizing factors of an enzyme are broken
- Reaction rate declines as the temperature is further increased
- Native conformation of the enzyme is disrupted
14
Q
pH
A
- Measure of [H+] of a solution
- (-) log [H+] = log 1/[H+]
15
Q
Functional groups
A
- Side chains of amino acids
- Can function as weak acids
- Perform acid/base interactions
- Degree of ionization changes as pH fluctuates
