Enzymes

Question 1

What is the nature of Enzyme

Answer 1

Globular Proteins

Question 2

What is the part substrates binding to called

Answer 2

Active site

Question 3

How does enzyme works

Answer 3

It speeds up chemical reaction by providing an alternative pathway with lower activation energy without itself being changed

Question 4

What are the 6 classes of enzymes

Answer 4

Ligase
Transferase
Oxidoreductase
Lyase
Hydrolase
Isomerase

Question 5

What contributes to the specficity of active site and orients the subtrate to the correct position

Answer 5

3D Arrangement of amino acids

Question 6

What model describes the specificity of enzyme

Answer 6

Lock-and-key model

Question 7

Name the 3 interactions between substrate and the amino acids

Answer 7

Hydrophobic interactions. hydrogen bonds, electrostatic interactions

Question 8

What does the induced-fit model imply

Answer 8

The active site isnt rigid
It is flexible and will be repositioned by the enzymes to interact with the subtrate

Question 9

What is the largest induced fit known

Answer 9

Hexokinase

Question 10

What is the Michaelis-Menten equation

Answer 10

Vi=K(max)[S]/ (Km+S), where Vi= rate,

K max=maximum velocity reached at infinite amount of subtrate

Km is the concentration of subtrate required to achiev half of K max

S=Subtrate concentration

Question 11

Does a high Km indicates high or low affinity of subtrate to the enzyme hence the activation energy

Answer 11

Low affinity, Lower activation energy

Question 12

How can pH affect the confrontmation of active site

Answer 12

It causes ionization of the side chain or AMino acids

Question 13

What is the criteria for being a reversible inhibitor

Answer 13

It should dissociate from the enzyme at a signifcant rate

Question 14

Name the three class under reversible inhibitors

Answer 14

Uncompetitive, non-competitive, competitive

Question 15

Is that true that the product of all enzymes are reversible inhibotors?

Answer 15

Ys

Question 16

What binds to allosteric site? What’s the pro of the mechanism

Answer 16

Allosteric activators or inhibitors. It has much stronger effect on enzyme velocity then those binding to active site.

It has rapid effect

Question 17

Name 1 example of covalent modification

Answer 17

Phosphorylation, which involves adding phosphate group to specific serine, theronine or tyrosine residue to affect ionic interactions or H bond patterns at the active site

Question 18

What is the irreversible modificaiton to enzyme

Answer 18

Proteolytic cleavage (to cleave Proenzymes to make them active)

Question 19

Name another way except for enzyme modification can the body regulate the rate of metabolism?

Answer 19

Regulate protein synthesis or degradation. It is slow and for long term