Enzymes

Question 1

What are the two models that explains Enzyme substrate binding

Answer 1

Induced-Fit model
Lock and Key model

Question 2

What are the two subclasses under Co factors

Answer 2

Metal Ions
Co enzymes

Question 3

What are the two subclasses of Co enzymes

Answer 3

Co substrates
Prosthetic groups

Question 4

Whats the difference between Cosubstrates and Prosthetic Groups

Answer 4

Prosthetic groups are tightly bound to the enzyme where as Co substrates are transient andd bind only when needed

Question 5

What are the two types of Enzymes that require Metal ions as co factors

Answer 5

Metalloenzymes and
Metal-activated enzymes

Question 6

What are the difference between Metalloenzymes and metal activated enzymes

Answer 6

Metalloenzymes have tightly bound metal ion cofactors where as metal-activated enzymes are activated by metal-ion cofactors

Question 7

What converts a zymogen into its active form

Answer 7

The cleavage or removal of a polypeptide segment from the protein

Question 8

What is saturation kinetics of enzymes

Answer 8

This is when There is an increase in the substrate concentration but there is no increase in Initial velocity
Hence the enzyme has reached a point where theyre saturated with the substrate

Question 9

What is the michaelis Menten constant(Km)

Answer 9

The concentration of the substrate required to reach half of Vmax

Question 10

What does a high Km mean

Answer 10

The enzyme has a low affinity for its substrate

Question 11

What is Enzyme inhibition

Answer 11

Altering the kinetic parameters of an enzyme catalyzed reaction by an inhibitor

Question 12

What are the two broad categories of enzyme inhibition

Answer 12

Reversible Inhibition
Irreversible inhibition

Question 13

What are the types of reversible Enzyme Inhibition

Answer 13

Competitive Inhibition
Noncompetitive Inhibition
Uncompetitive Inhibition

Question 14

On the double reciprocal plot for competitive inhibition, what are the key factors on the graph

Answer 14

Vmax remains unchanged
But Km increases

Question 15

Usually how are competitive inhibitors able to bind to the same active sites as the substrates

Answer 15

theyre usually structural analogues of the the substrates

Question 16

Give examples of Competitive inhibitors and the Enzymes they inhibit

Answer 16

Methotrexate-Dihydrofolate reductase(prevents production of Tetrahydrofolate in DNA synthesis in bacteria)

Sulfanamides - PABA(Also affect Folate synthesis in bacteria)

Statin drugs - HMG CoA Reductase(Prevent the synthesis of Cholestrol)

Question 17

In Non competitive inhibiton Describe the key features of the Double reciprocal Graph

Answer 17

The Vmax decreases
But the Km remains the same

Question 18

Give an example of a non-competitive inhibitor and the enzymeit inhibits

Answer 18

Non-nucleoside Reverse Transcriptase inhibitor(Nevirapine)- viral enzyme HIV-1 reverse transcriptase

Heavy metal poisoning- makes enzyme inactive

Question 19

WHich type of Inhibitor only binds to the Enzyme substrate complex after it has been formed

Answer 19

Uncompetitive inhibitor

Question 20

what are the key features of The double reciprocal plot of Uncompetitive inhibition

Answer 20

The Vmax Decreases
Km decreases

Question 21

What are the two types of Irreversible inhibitors

Answer 21

Covalent
Suicide inhibitors

Question 22

Give an example of a covalent inhibitor

Answer 22

Di-isopropyl fluorophosphate(DIPF)- inhibition of acetylcholinesterase