Flashcards in Enzyme Kinetics Deck (19):

1

## The velocity (v) of a simple reaction is measured by the disappearance of reactant (A) or by the appearance of product (P) per unit time, and is a function of the concentration of reactant. What is the equation for this?

### v = d[P]/dt = -d[A]/dt = k[A]

2

## give the velocity equation for a zero order reaction

### v= k

3

## give the velocity equation for a first order reaction

### v = k[A]

4

## give the velocity equation for a second order reaction

### v = k[A]^2

5

## What are the assumptions of the michaelis-menten equation?

###
1.use only initial velocities, then [P] = 0 and therefore k4 can be ignored

2. [ES] is constant, the "steady state" assumption

6

## What is the michaelis-menten equation?

### v = Vmax [S] / Km + [S]

7

## When does Vmax = K3 [Etotal]

### When [S] is very high, the enzyme will be saturated with S such that [ES] = [Etotal]

8

## What does it mean in terms of saturation, for an enzyme to be at Vmax

### since the enzyme is saturated with S, adding more S will not result in an increase in activity - this represents Vmax

9

## Km = ?

### (k3 + k2) / k1

10

## At very low [S], the change in velocity with [S] approximates a linear response. This region is ____-____ order kinetics

### pseudo-first

11

## At very high [S], the velocity approaches Vmax in an asymptotic fashion. This region represents ____-____ order kinetics (the v no longer varies with an increase in [S]

### pseudo-zero

12

## The Km equals the [S] at which the velocity is what?

### one-half maximum

13

## Enzymes with lower Km, are said to have a ___ affinity for their substrates than enzymes with a higher Km

### greater

14

## A lower Km means a lower Km means a lower concentration of S is required to achieve what?

### 1/2 Vmax

15

##
Since Km represents (k3 + k2) / k1, a low Km means ___ of ES is more rapid than the ___ of ES

S + E -> ES -> E + P

### formation; breakdown

16

## In most cases, k3 is the ___ ____ step in catalysis, and therefore may be called kcat, or the turnover number

### rate limiting

17

## If one knows the Vmax, and [Etotal], the value of kcat can be calculated and will be what?

### the moles of product formed per mole of enzyme per unit time, at maximum velocity

18

## give the equation for the lineweaver-Burk plot

###
reciprocal of michaelis-menten

1/v = (Km/Vm)(1/S) + 1/Vm

19