MB+B Enzymes

Question 1

What are the 6 types of enzyme

Answer 1

Oxidoreductases
Transferases
Hydrolases
Lyases
Isomerases
Ligases

Question 2

What is Keq

Answer 2

The equalibrium constant = [B]/[A]

Question 3

Why is the relationship between substrate concentration and rate non-linear

Answer 3

The reaction becomes saturated and the enzyme becomes the limiting factor and reaction slows as it approaches maximum value

Question 4

What is Vmax

Answer 4

The maximum rate a reaction can achieve

Question 5

What is Km

Answer 5

Michaelis constant = Vmax/2

Question 6

When is the michaelis menten equation used

Answer 6

To get an accurate measurement of Km

Question 7

What is the michaelis menten equation

Answer 7

V= Vmax x [S] / Km + [S]

Question 8

What assumptions does the michaelis menten equation rely on

Answer 8

The step from the formation of the enzyme substrate complex to product is irresversable
Substrate is in abundance
ESC is at a steady state (unchangeable over time)

Question 9

What is Etot

Answer 9

[E] + [ES]

Question 10

What does the line weaver - burn plot do

Answer 10

Converts curved rate graphs into straight line so Kmax and Km can be calculated

Question 11

What is the equation for the line weaver burk plot

Answer 11

1/V = Km x1/Vmax[S] + 1/Vmax

Question 12

In extreme lock and key method what is the effect on the reaction

Answer 12

ES decreases
No stabilising effect on ESt so increases
Vmax and Km decrease

Question 13

What’s the effect of the extreme induced fit model

Answer 13

No reliance on E + S binding
Vmax higher
As E doesn’t bind well more [S] needed to reach 1/2 Vmax so Km increases

Question 14

What Kcat

Answer 14

Number of moles of product formed per mol of enzyme per second

Question 15

What the equation for Kcat

Answer 15

Kcat = Vmax / Etot

Question 16

what is negative feedback inhibition

Answer 16

high concentrations of product cause inhibition of enzymes

Question 17

CTP regulates binding in what way

Answer 17

When CTP binds the quaternary structure changes shape causing active site to not be formed preventing the formation of enzyme substrate complexes
stabilizes the t site prevening transition into the rstate that will more readily accept substrate

Question 18

Mechanisms of Enzyme Catalysis

Answer 18

• Covalent catalysis (serine proteases)* Acid-base catalysis (serine proteases and carbonic anhydrase)* Metal ion catalysis (carbonic anhydrase)* Proximity and orientation effects (serine proteases, CA, ATCase)* Electrostatic catalysis (serine proteases)* Preferential binding to transition state (transition state stabilization) (serine proteases

Question 19

advantages of using enzymes in biotechnology

Answer 19

stereospecific
Regiospecificity
Substrate specificity
Easy to manipulate / engineer biologicalsystems to alter their properties
Natural Biodiversity
Reproducibility / cost

Question 20

disadvantages of enzymes in biotech

Answer 20

limited temp range
limited pH range
sensitive to organic solvents

Question 21

ways around the disadvantages of enzymes in biotech

Answer 21

the use of extremophile enzymes

Question 22

pros and cons of using enzymes in vitro

Answer 22

Pro:* Optimise and control simple reaction conditions (pH, conc, temp.)* Simple product purification (less contaminants than cells)* No biological contamination problems

Cons:* Enzyme must be isolated from a cell* Pure proteins not stable indefinitely* Some reactions require specific inputs (e.g. ATP / NADPH driven reactions)

Question 23

pros and cons of using enzyme in vivo

Answer 23

Pro:* Cheap and easy to grow many microorganisms* Link multiple reactions* Controlled intracellular environment ideal for enzyme function

Cons:* Biological contamination problematic in drug formulation* Potential problems transporting enzyme substrates into cells* Unwanted downstream processing of product by organism

Question 24

how would you manipulate enzyme protein sequence for better performance

Answer 24

Use site-directed mutagenesis to alter sequence of gene encoding an enzyme